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Overview

Affected versions of this package are vulnerable to Regular Expression Denial of Service (ReDoS) due to the globEscape function. An attacker can send specially crafted inputs that exploit inefficient regular expression complexity.

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

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to HTTP Request Smuggling in the processHeader() while handling HTTP/1.1 requests containing duplicate Content-Length headers with differing casing. An attacker can bypass access controls, poison caches, hijack credentials, or cause service disruption by sending specially crafted HTTP requests that are interpreted inconsistently by proxies and backend servers.

Remediation

Upgrade undici to version 6.24.0, 7.24.0 or higher.

References

• GitHub Commit
• HackerOne Report
• Red Hat Bugzilla Bug

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to HTTP Request Smuggling due to the interceptors.retry() flow in lib/handler/retry-handler.js. An attacker can cause a proxy or gateway that forwards Undici responses to emit a body whose length does not match the Content-Length header by sending a partial 206 response with mismatched framing and closing the connection to trigger a retry or resume. This can corrupt downstream HTTP framing, causing client or intermediary hangs and response parsing errors, and can expose users of the forwarding service to broken responses or connection desynchronization.

Remediation

Upgrade undici to version 6.28.0, 7.29.0, 8.9.0 or higher.

References

• GitHub Advisory
• GitHub Commit

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Improper Neutralization via unsanitized domain handling and unparsed attribute serialization in lib/web/cookies/util.js. An attacker can inject or override cookie attributes by supplying a crafted domain such as example.com; SameSite=None or an unparsed entry such as X-Custom=val; HttpOnly to setCookie. When applications pass user-controlled tenant or routing data into these fields, the serialized Set-Cookie header can carry attacker-chosen flags like SameSite, Secure, or HttpOnly. This can weaken CSRF protections, alter cookie visibility to scripts, or change how the browser sends the cookie.

Remediation

Upgrade undici to version 6.28.0, 7.29.0, 8.9.0 or higher.

References

• GitHub Commit v6.28.0
• Maintainer's Advisory

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Time-of-check Time-of-use (TOCTOU) Race Condition in the HTTP/1.1 client when an attacker-controlled upstream server injects an unsolicited response onto an idle keep-alive socket after a request completes. An attacker can cause responses to be delivered to the wrong requests by sending crafted HTTP responses through a compromised or malicious upstream server.

Note: This is only exploitable if the upstream HTTP/1.1 server is attacker-controlled or compromised and keep-alive connection reuse is enabled.

Workaround

This vulnerability can be mitigated by disabling keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

Remediation

Upgrade undici to version 6.27.0, 7.28.0, 8.5.0 or higher.

References

• GitHub Advisory
• GitHub Commit
• GitHub Commit
• GitHub Commit
• GitHub Release
• GitHub Release
• GitHub Release
• HackerOne Report
• Vendor Advisory

Overview

uuid is a RFC4122 (v1, v4, and v5) compliant UUID library.

Affected versions of this package are vulnerable to Improper Validation of Specified Index, Position, or Offset in Input due to accepting external output buffers but not rejecting out-of-range writes (small buf or large offset). This inconsistency allows silent partial writes into caller-provided buffers.

PoC

cd /home/StrawHat/uuid
npm ci
npm run build

node --input-type=module -e "
import {v4,v5,v6} from './dist-node/index.js';
const ns='6ba7b810-9dad-11d1-80b4-00c04fd430c8';
for (const [name,fn] of [
  ['v4',()=>v4({},new Uint8Array(8),4)],
  ['v5',()=>v5('x',ns,new Uint8Array(8),4)],
  ['v6',()=>v6({},new Uint8Array(8),4)],
]) {
  try { fn(); console.log(name,'NO_THROW'); }
  catch(e){ console.log(name,'THREW',e.name); }
}"

Remediation

Upgrade uuid to version 11.1.1, 14.0.0 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Release

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via the decompression chain. An attacker can cause high CPU usage and excessive memory allocation by sending HTTP responses with a large number of chained compression steps in the Content-Encoding header.

Remediation

Upgrade undici to version 6.23.0, 7.18.2 or higher.

References

• GitHub Commit
• GitHub Commit
• GitHub Release

Overview

undici is an An HTTP/1.1 client, written from scratch for Node.js

Affected versions of this package are vulnerable to CRLF Injection via the upgrade option of the client.request() function. An attacker can inject malicious data into HTTP headers or prematurely terminate HTTP requests by sending specially crafted input, potentially leading to unauthorized information disclosure or bypassing of security controls.

Remediation

Upgrade undici to version 6.24.0, 7.24.0 or higher.

References

• GitHub Commit
• HackerOne Report
• Red Hat Bugzilla Bug