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Overview

@sigstore/verify is a Verification of Sigstore signatures

Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature due to the certificateOIDs option being accepted by the public API but discarded before verification, resulting in required certificate extension OIDs never being checked. An attacker can bypass intended certificate extension constraints by presenting unauthorized certificates that satisfy the remaining verification checks.

Remediation

Upgrade @sigstore/verify to version 3.1.1 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

pacote is a JavaScript package downloader

Affected versions of this package are vulnerable to Denial of Service (DoS) via the addGitSha function. An attacker can exploit this vulnerability by supplying a specially crafted spec.rawSpec value that triggers the function’s regex replacement and string-manipulation logic, causing excessive CPU consumption and potentially stalling or crashing the process.

PoC

const addGitSha = require('pacote/lib/util/add-git-sha');

var str = "";
for (var i = 0; i < 1000000; i++) {
  str += "#";
}
str += "\n@";

const spec = {
  rawSpec: str,
  hosted: null,
};

console.log("start");
addGitSha(spec, "");
console.log("end");

// run `npm install pacote` and `node attack.js` 
// then the program will stuck forever with high CPU usage

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 pacote to version 21.5.1 or higher.

References

• GitHub Commit
• Vulnerable Code

Overview

sigstore is a code-signing for npm packages

Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature due to the certificateOIDs option being accepted by the public API but discarded before verification, resulting in required certificate extension OIDs never being checked. An attacker can bypass intended certificate extension constraints by presenting unauthorized certificates that satisfy the remaining verification checks.

Remediation

Upgrade sigstore to version 4.1.1 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

Affected versions of this package are vulnerable to Directory Traversal via unsanitized input in the prefix, postfix, or dir parameters during path construction. An attacker can create files outside the intended temporary directory, potentially overwriting or placing files in sensitive locations, by supplying crafted values containing traversal sequences or absolute paths.

Note:

The fix for this issue was incomplete and led to a bypass, known as CVE-2026-49982. Users are recommended to upgrade to version 0.2.7 to get a complete fix for this issue.

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 tmp to version 0.2.6 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

Affected versions of this package are vulnerable to Directory Traversal due to the improper sanitization of non-string values in the prefix, postfix, or dir parameters during path construction. An attacker can create files outside the intended temporary directory, potentially overwriting or placing files in sensitive locations, by supplying crafted values containing traversal sequences or absolute paths.

Note:

This issue is due to an incomplete fix for CVE-2026-44705. Added _assertPath as a guard does not account for non-string values.

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 tmp to version 0.2.7 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

@faker-js/faker is a Generate massive amounts of fake contextual data

Affected versions of this package are vulnerable to Eval Injection via the helpers.fake function. An attacker can execute arbitrary JavaScript code by supplying specially crafted templates that access the Function constructor through fakeEval.resolveProperty when a function returns another function.

Remediation

Upgrade @faker-js/faker to version 10.5.0 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub PR

Overview

useragent allows you to parse user agent string with high accuracy by using hand tuned dedicated regular expressions for browser matching.

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) when passing long user-agent strings.

This is due to incomplete fix for this vulnerability: https://snyk.io/vuln/SNYK-JS-USERAGENT-11000.

An attempt to fix the vulnerability has been pushed to master.

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

A fix was pushed into the master branch but not yet published.

References

• GitHub Commit

• GitHub PR

• GitHub PR

• GitHub PR

• Hackerone Report