TI-2024-15657 Aliases CVE-2024-23638

SQUID-2023:11 Denial of Service in Cache Manager

MEDIUM 63CWE-825Published 2024-01-23 · Updated 2025-06-17

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · None · High
Fix status: Partial Red Hat: 2 fixed, 2 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

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`.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV

EPSS 0.6005 99th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Partial squid (squid-cache): 6.6Red Hat: 2 advisoriesRed Hat: 2 fixed, 2 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: Poc
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
squid-cache	squid	before 6.6	6.6	Patch available	CNA

squid Vendorsquid-cache Affected before 6.6 Fixed in 6.6 Patch available CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:squid-cache:squid::::::::	5.0 – 5.9; 6.0 to before 6.6	Vulnerable	squid-cache

cpe:2.3:a:squid-cache:squid:*:*:*:*:*:*:*:* Versions 5.0 – 5.9; 6.0 to before 6.6 Vulnerable ·squid-cache

Remediation

Fix · CNA squid (squid-cache) Fixed in 6.6

Red Hat 2 advisories

RHSA-2024:9644 Released 2024-11-14 · Red Hat rating Important
squid:4 security update
- Red Hat Enterprise Linux AppStream (v. 8) libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.aarch64::squid:4, libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.ppc64le::squid:4, libecap-1.0.1-2.module+el8.9.0+19703+a1da7223.s390x::squid:4 +11
RHSA-2024:4861 Released 2024-07-25 · Red Hat rating Moderate
squid security update
- Red Hat Enterprise Linux AppStream (v. 9) squid-7:5.5-13.el9_4

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Red Hat Enterprise Linux 6	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux 7	Affected	No fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)	Fixed	RHSA-2024:9644
Red Hat Enterprise Linux AppStream (v. 9)	Fixed	RHSA-2024:4861

Timeline

2026-10-02 Threatist record created from CVE-2024-23638

References

Exploit 1

https://megamansec.github.io/Squid-Security-Audit/stream-assert.html

Patch 4

Advisory 1

https://github.com/squid-cache/squid/security/advisories/GHSA-j49p-553x-48rx

Other 3

TI-2025-38486 Squid vulnerable to information disclosure via authentication credential leakage in error handling CVSS 3.1CRITICAL 10.0
TI-2024-16845 Denial of Service in HTTP Header parser in squid proxy CVSS 3.1HIGH 7.5
TI-2024-16566 SQUID-2024:1 Denial of Service in HTTP Chunked Decoding CVSS 3.1HIGH 8.6
TI-2023-26921 Denial of Service in HTTP Message Processing in Squid CVSS 3.1HIGH 8.6
TI-2023-27496 SQUID-2023:10 Denial of Service in HTTP Request parsing CVSS 3.1HIGH 8.6
TI-2023-25306 Squid: denial of service in http digest authentication CVSS 3.1HIGH 8.6

See all 110 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences