---
id: CVE-2023-6193
aliases:
  - GHSA-w3vp-jw9m-f9pm
title: Unbounded queuing of path validation messages in cloudflare-quiche
summary: Unbounded queuing of path validation messages in cloudflare-quiche
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
vendor: quiche
product: quiche
ecosystem: rust
affected:
  - 'quiche >= 0.15.0, < 0.19.1'
patched:
  - quiche 0.19.1
published: '2023-12-13'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-w3vp-jw9m-f9pm'
references:
  - url: >-
      https://github.com/cloudflare/quiche/security/advisories/GHSA-w3vp-jw9m-f9pm
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2023-6193'
  - url: >-
      https://github.com/cloudflare/quiche/commit/ea7ecf39ae28ab24cf1785c1674dc2e8a076f9ca
  - url: 'https://datatracker.ietf.org/doc/html/rfc9000#section-8.2'
  - url: 'https://github.com/cloudflare/quiche'
tags:
  - osv
  - rust
epss: 0.00763
epssPercentile: 0.535
ingestedAt: '2026-07-09T18:56:37.335Z'
---

## Overview

### Impact
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](https://datatracker.ietf.org/doc/html/rfc9000#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.

### Patches
Quiche versions greater than 0.19.0 address this problem.

### References
[CVE-2023-6193](https://www.cve.org/CVERecord?id=CVE-2023-6193)
[RFC 9000 Section 8.2](https://datatracker.ietf.org/doc/html/rfc9000#section-8.2)

## Affected packages

- `quiche >= 0.15.0, < 0.19.1`

## Remediation

Upgrade to a patched release:

- `quiche 0.19.1`