CVE catalog

CVE-2026-33526

Severity: Critical · CVSS 9.2
Published: Mar 24, 2026, 11:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 9.08% · Oct 25, 2026

Squid is a caching proxy for the Web. Prior to version 7.5, due to heap Use-After-Free, Squid is vulnerable to Denial of Service when handling ICP traffic. This problem allows a remote attacker to perform a reliable and repeatable Denial of Service attack against the Squid service using ICP protocol. This attack is limited to Squid deployments that explicitly enable ICP support (i.e. configure non-zero `icp_port`). This problem _cannot_ be mitigated by denying ICP queries using `icp_access` rules. Version 7.5 contains a patch.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	squid	sid	`7.7-1`	fixed
Debian	squid	forky	`7.7-1`	fixed
Debian	squid	trixie	`6.13-2+deb13u3`	fixed
Debian	squid	trixie-security	`6.13-2+deb13u2`	fixed
Debian	squid	bookworm	`5.7-2+deb12u5`	vulnerable
Debian	squid	bookworm-security	`5.7-2+deb12u6`	fixed
Cpe	squid	Not reported	Not reported	vulnerable
Cpe	squid	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squid-cgi	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squid-common	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squid-openssl	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squid-purge	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squidclient	Not reported	`6.14-0ubuntu0.24.04.2`	fixed
Cpe	squid	Not reported	`7.5`	fixed
Ubuntu	squid	noble	`6.14-0ubuntu0.24.04.5`	fixed
Ubuntu	squid-cgi	noble	`6.14-0ubuntu0.24.04.5`	fixed
Ubuntu	squid-common	noble	`6.14-0ubuntu0.24.04.5`	fixed
Ubuntu	squid-openssl	noble	`6.14-0ubuntu0.24.04.5`	fixed
Ubuntu	squid-purge	noble	`6.14-0ubuntu0.24.04.5`	fixed
Ubuntu	squidclient	noble	`6.14-0ubuntu0.24.04.5`	fixed
Suse	squid	linux enterprise module for server applications 15 sp7	`6.14-150600.3.20.1`	fixed
Suse	squid	linux enterprise server 15 sp6-ltss	`6.14-150600.3.20.1`	fixed
Suse	squid	linux enterprise server for sap applications 15 sp6	`6.14-150600.3.20.1`	fixed
Ubuntu	squid3	pro	`3.5.23-5ubuntu1`	vulnerable
Ubuntu	squid3	pro	`3.5.23-5ubuntu2`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.1`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.2`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.3`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.4`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.5`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.6`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.7`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.8`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.9`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.10`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.11`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.12`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.13`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm1`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm2`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm3`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm4`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm5`	vulnerable
Ubuntu	squid3	pro	`3.5.27-1ubuntu1.14+esm6`	fixed
Ubuntu	squid	pro	`4.8-1ubuntu2`	vulnerable
Ubuntu	squid	pro	`4.8-1ubuntu3`	vulnerable
Ubuntu	squid	pro	`4.9-2ubuntu1`	vulnerable
Ubuntu	squid	pro	`4.9-2ubuntu2`	vulnerable
Ubuntu	squid	pro	`4.9-2ubuntu3`	vulnerable
Ubuntu	squid	pro	`4.9-2ubuntu4`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.1`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.2`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.3`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.4`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.5`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.6`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.7`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.8`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.9`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.10`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.11`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.12`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.13`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.13+esm1`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.13+esm2`	vulnerable
Ubuntu	squid	pro	`4.10-1ubuntu1.13+esm3`	fixed
Ubuntu	squid	22.04	`4.13-10ubuntu5`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu1`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu3`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu4`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu4.1`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu4.2`	vulnerable
Ubuntu	squid	22.04	`5.2-1ubuntu4.3`	vulnerable
Ubuntu	squid	22.04	`5.7-0ubuntu0.22.04.1`	vulnerable
Ubuntu	squid	22.04	`5.7-0ubuntu0.22.04.2`	vulnerable
Ubuntu	squid	22.04	`5.7-0ubuntu0.22.04.3`	vulnerable
Ubuntu	squid	22.04	`5.7-0ubuntu0.22.04.4`	vulnerable
Ubuntu	squid	22.04	`5.9-0ubuntu0.22.04.1`	vulnerable
Ubuntu	squid	22.04	`5.9-0ubuntu0.22.04.2`	vulnerable
Ubuntu	squid	22.04	`5.9-0ubuntu0.22.04.3`	vulnerable
Ubuntu	squid	22.04	`5.9-0ubuntu0.22.04.4`	vulnerable
Ubuntu	squid	22.04	`5.9-0ubuntu0.22.04.5`	fixed
Ubuntu	squid	24.04	`6.1-2ubuntu1`	vulnerable
Ubuntu	squid	24.04	`6.1-2ubuntu2`	vulnerable
Ubuntu	squid	24.04	`6.5-1ubuntu1`	vulnerable
Ubuntu	squid	24.04	`6.5-1ubuntu2`	vulnerable
Ubuntu	squid	24.04	`6.5-1ubuntu3`	vulnerable
Ubuntu	squid	24.04	`6.6-1ubuntu4`	vulnerable
Ubuntu	squid	24.04	`6.6-1ubuntu5`	vulnerable
Ubuntu	squid	24.04	`6.6-1ubuntu5.1`	vulnerable
Ubuntu	squid	24.04	`6.10-0ubuntu0.24.04.1`	vulnerable
Ubuntu	squid	24.04	`6.13-0ubuntu0.24.04.1`	vulnerable
Ubuntu	squid	24.04	`6.13-0ubuntu0.24.04.2`	vulnerable
Ubuntu	squid	24.04	`6.13-0ubuntu0.24.04.3`	vulnerable
Ubuntu	squid	24.04	`6.14-0ubuntu0.24.04.1`	vulnerable
Ubuntu	squid	24.04	`6.14-0ubuntu0.24.04.2`	fixed
Ubuntu	squid	25.10	`6.13-1ubuntu1`	vulnerable
Ubuntu	squid	25.10	`6.13-1ubuntu2`	vulnerable
Ubuntu	squid	25.10	`6.13-1ubuntu3`	vulnerable
Ubuntu	squid	25.10	`6.13-1ubuntu4`	vulnerable
Ubuntu	squid	25.10	`6.13-1ubuntu4.1`	vulnerable
Ubuntu	squid	25.10	`6.14-0ubuntu0.25.10.1`	vulnerable
Ubuntu	squid	25.10	`6.14-0ubuntu0.25.10.2`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	squid	source	sid	`7.5-1`	not yet assigned	Not reported	Not reported
Debian	squid	source	forky	`7.5-1`	not yet assigned	Not reported	Not reported
Debian	squid	source	trixie	`6.13-2+deb13u2`	not yet assigned	Not reported	Not reported
Debian	squid	source	bookworm	`5.7-2+deb12u6`	not yet assigned	Not reported	Not reported
Cpe	squid	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squid-cgi	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squid-common	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squid-openssl	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squid-purge	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squidclient	cpe	Not reported	`6.14-0ubuntu0.24.04.2`	Not reported	Not reported	Not reported
Cpe	squid	cpe	Not reported	`7.5`	Not reported	Not reported	Not reported
Ubuntu	squid	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Ubuntu	squid-cgi	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Ubuntu	squid-common	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Ubuntu	squid-openssl	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Ubuntu	squid-purge	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Ubuntu	squidclient	deb	noble	`6.14-0ubuntu0.24.04.5`	Not reported	Not reported	Not reported
Suse	squid	rpm	linux enterprise module for server applications 15 sp7	`6.14-150600.3.20.1`	Not reported	SUSE-SU-2026:4621-1	Not reported
Suse	squid	rpm	linux enterprise server 15 sp6-ltss	`6.14-150600.3.20.1`	Not reported	SUSE-SU-2026:4621-1	Not reported
Suse	squid	rpm	linux enterprise server for sap applications 15 sp6	`6.14-150600.3.20.1`	Not reported	SUSE-SU-2026:4621-1	Not reported
Ubuntu	squid3	deb	pro	`3.5.27-1ubuntu1.14+esm6`	Not reported	UBUNTU-CVE-2026-33526	Not reported
Ubuntu	squid	deb	pro	`4.10-1ubuntu1.13+esm3`	Not reported	UBUNTU-CVE-2026-33526	Not reported
Ubuntu	squid	deb	22.04	`5.9-0ubuntu0.22.04.5`	Not reported	UBUNTU-CVE-2026-33526	Not reported
Ubuntu	squid	deb	24.04	`6.14-0ubuntu0.24.04.2`	Not reported	UBUNTU-CVE-2026-33526	Not reported
Ubuntu	squid	deb	25.10	`6.14-0ubuntu0.25.10.2`	Not reported	UBUNTU-CVE-2026-33526	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[squid]Affected
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
[squid-cgi]Affected
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
[squidclient]Affected
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
[squid-common]Affected
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · all · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · all · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
[squid-openssl]Affected
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
[squid-purge]Affected
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Affected · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 5.7-2+deb12u6
  nvd · squid · debian · bookworm; nvd · squid · debian · 12

[Debian 13 (Trixie)]

[squid]Fixed
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
[squid-cgi]Fixed
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
[squidclient]Fixed
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
[squid-common]Fixed
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
[squid-openssl]Fixed
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
[squid-purge]Fixed
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 6.13-2+deb13u2
  nvd · squid · debian · 13

Observed: Oct 27, 2026, 8:03:05 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]