Unbounded queuing of path validation messages in cloudflare-quiche

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2023-6193: 0.76% estimated exploitation activity in the next 30 days; percentile 55.44 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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) requires that the recipient of a PATHCHALLENGE frame responds by sending a PATHRESPONSE. An unauthenticated remote attacker can exploit the vulnerability by sending PATHCHALLENGE frames and manipulating the connection (e.g. by restricting the peer's congestion window size) so that PATHRESPONSE 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 RFC 9000 Section 8.2

Published by the source

13 Dec 2023, 13:34 UTC

Last modified by the source

13 Dec 2023, 13:34 UTC

Source last checked

26 Oct 2026, 15:37 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-w3vp-jw9m-f9pm

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# Patch Next advisory brief: CVE-2023-6193

Advisory: Unbounded queuing of path validation messages in cloudflare-quiche
IDs: CVE-2023-6193, GHSA-w3vp-jw9m-f9pm
Record: https://patchnext.com/advisories/cve-2023-6193 (revision 1, source checked 26 Oct 2026, 15:37 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: quiche 0.19.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- crates.io quiche: affected >= 0.15.0, < 0.19.1; fixed in 0.19.1

## Suggested inspection (read-only)
- crates.io quiche: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on quiche.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-w3vp-jw9m-f9pm (GitHub-reviewed advisory GHSA-w3vp-jw9m-f9pm lists affected ranges: crates.io quiche >=0.15.0 <0.19.1)

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