CVE catalog

CVE-2020-15810

squid: CVE-2020-15810

Severity: Critical · CVSS 9.6CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N
Published: Aug 23, 2020, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 2.43% · Oct 25, 2026

An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream.

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`	fixed
Debian	squid	bookworm-security	`5.7-2+deb12u6`	fixed
Alpine	squid	3.10	`4.13-r0`	fixed
Alpine	squid	3.11	`4.13-r0`	fixed
Alpine	squid	3.12	`4.13-r0`	fixed
Alpine	squid	3.13	`4.13.0-r0`	fixed
Alpine	squid	3.14	`4.13.0-r0`	fixed
Alpine	squid	3.15	`4.13.0-r0`	fixed
Alpine	squid	3.16	`4.13.0-r0`	fixed
Alpine	squid	3.17	`4.13.0-r0`	fixed
Alpine	squid	3.18	`4.13.0-r0`	fixed
Alpine	squid	3.19	`4.13.0-r0`	fixed
Alpine	squid	3.20	`4.13.0-r0`	fixed
Alpine	squid	3.21	`4.13.0-r0`	fixed
Alpine	squid	3.22	`4.13.0-r0`	fixed
Alpine	squid	3.23	`4.13.0-r0`	fixed
Alpine	squid	3.24	`4.13.0-r0`	fixed
Alpine	squid	3.9	`4.13-r0`	fixed
Ubuntu	squid	20.04	`4.8-1ubuntu2`	vulnerable
Ubuntu	squid	20.04	`4.8-1ubuntu3`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu1`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu2`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu3`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu4`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1.1`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1.2`	fixed
Ubuntu	squid3	16.04	`3.3.8-1ubuntu16`	vulnerable
Ubuntu	squid3	16.04	`3.3.8-1ubuntu17`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu6`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.1`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.2`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.3`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.4`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.5`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.6`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.7`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.8`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.9`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.10`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.11`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.12`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.13`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.14`	vulnerable
Ubuntu	squid3	16.04	`3.5.12-1ubuntu7.15`	fixed
Ubuntu	squid3	18.04	`3.5.23-5ubuntu1`	vulnerable
Ubuntu	squid3	18.04	`3.5.23-5ubuntu2`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.1`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.2`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.3`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.4`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.5`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.6`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.7`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.8`	vulnerable
Ubuntu	squid3	18.04	`3.5.27-1ubuntu1.9`	fixed
Ubuntu	squid	20.04	`4.8-1ubuntu2`	vulnerable
Ubuntu	squid	20.04	`4.8-1ubuntu3`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu1`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu2`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu3`	vulnerable
Ubuntu	squid	20.04	`4.9-2ubuntu4`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1.1`	vulnerable
Ubuntu	squid	20.04	`4.10-1ubuntu1.2`	fixed
Suse	squid3	linux enterprise point of sale 11 sp3	`3.1.23-8.16.37.15.1`	fixed
Suse	squid3	linux enterprise server 11 sp4-ltss	`3.1.23-8.16.37.15.1`	fixed
Suse	squid	hpe helion openstack 8	`3.5.21-26.32.1`	fixed
Suse	squid	openstack cloud 7	`3.5.21-26.32.1`	fixed
Suse	squid	openstack cloud 8	`3.5.21-26.32.1`	fixed
Suse	squid	openstack cloud 9	`3.5.21-26.32.1`	fixed
Suse	squid	openstack cloud crowbar 8	`3.5.21-26.32.1`	fixed
Suse	squid	openstack cloud crowbar 9	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server for sap applications 12 sp2	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server for sap applications 12 sp3	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server for sap applications 12 sp4	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server 12 sp2-ltss	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server 12 sp2-bcl	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server 12 sp3-ltss	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server 12 sp3-bcl	`3.5.21-26.32.1`	fixed
Suse	squid	linux enterprise server 12 sp4-ltss	`3.5.21-26.32.1`	fixed
Suse	squid	enterprise storage 5	`3.5.21-26.32.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	squid	source	sid	`4.13-1`	not yet assigned	Not reported	[968934]
Debian	squid	source	forky	`4.13-1`	not yet assigned	Not reported	[968934]
Debian	squid	source	trixie	`4.13-1`	not yet assigned	Not reported	[968934]
Debian	squid	source	bookworm	`4.13-1`	not yet assigned	Not reported	[968934]
Alpine	squid	apk	3.10	`4.13-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.11	`4.13-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.12	`4.13-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.13	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.14	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.15	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.16	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.17	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.18	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.19	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.20	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.21	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.22	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.23	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.24	`4.13.0-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Alpine	squid	apk	3.9	`4.13-r0`	Not reported	ALPINE-CVE-2020-15810	Not reported
Ubuntu	squid	deb	20.04	`4.10-1ubuntu1.2`	Not reported	USN-4477-1	Not reported
Ubuntu	squid3	deb	16.04	`3.5.12-1ubuntu7.15`	Not reported	UBUNTU-CVE-2020-15810	Not reported
Ubuntu	squid3	deb	18.04	`3.5.27-1ubuntu1.9`	Not reported	UBUNTU-CVE-2020-15810	Not reported
Ubuntu	squid	deb	20.04	`4.10-1ubuntu1.2`	Not reported	UBUNTU-CVE-2020-15810	Not reported
Suse	squid3	rpm	linux enterprise point of sale 11 sp3	`3.1.23-8.16.37.15.1`	Not reported	SUSE-SU-2020:14590-1	Not reported
Suse	squid3	rpm	linux enterprise server 11 sp4-ltss	`3.1.23-8.16.37.15.1`	Not reported	SUSE-SU-2020:14590-1	Not reported
Suse	squid	rpm	hpe helion openstack 8	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	openstack cloud 7	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	openstack cloud 8	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	openstack cloud 9	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	openstack cloud crowbar 8	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	openstack cloud crowbar 9	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server for sap applications 12 sp2	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server for sap applications 12 sp3	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server for sap applications 12 sp4	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server 12 sp2-ltss	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server 12 sp2-bcl	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server 12 sp3-ltss	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server 12 sp3-bcl	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	linux enterprise server 12 sp4-ltss	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported
Suse	squid	rpm	enterprise storage 5	`3.5.21-26.32.1`	Not reported	SUSE-SU-2020:2471-1	Not reported

[Debian bug #968934]

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[squid]Unknown
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squidclient]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-common]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12

[Debian 13 (Trixie)]

[squid]Unknown
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
[squidclient]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
[squid-common]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.13-1
  dsa · squid · debian · 13

Observed: Oct 23, 2026, 5:48:26 PM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]