CVE catalog

CVE-2018-1000027

squid: CVE-2018-1000027

Severity: Medium · CVSS 6.8CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H
Published: Jan 19, 2018, 12:00:00 AM UTC
Source: [NVD] · [CVE record]
EPSS: 12.91% · Oct 27, 2026

The Squid Software Foundation Squid HTTP Caching Proxy version prior to version 4.0.23 contains a NULL Pointer Dereference vulnerability in HTTP Response X-Forwarded-For header processing that can result in Denial of Service to all clients of the proxy. This attack appear to be exploitable via Remote HTTP server responding with an X-Forwarded-For header to certain types of HTTP request. This vulnerability appears to have been fixed in 4.0.23 and later.

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	`3.5.27-r2`	fixed
Alpine	squid	3.11	`3.5.27-r2`	fixed
Alpine	squid	3.12	`3.5.27-r2`	fixed
Alpine	squid	3.13	`3.5.27-r2`	fixed
Alpine	squid	3.14	`3.5.27-r2`	fixed
Alpine	squid	3.15	`3.5.27-r2`	fixed
Alpine	squid	3.16	`3.5.27-r2`	fixed
Alpine	squid	3.17	`3.5.27-r2`	fixed
Alpine	squid	3.18	`3.5.27-r2`	fixed
Alpine	squid	3.19	`3.5.27-r2`	fixed
Alpine	squid	3.20	`3.5.27-r2`	fixed
Alpine	squid	3.21	`3.5.27-r2`	fixed
Alpine	squid	3.22	`3.5.27-r2`	fixed
Alpine	squid	3.23	`3.5.27-r2`	fixed
Alpine	squid	3.24	`3.5.27-r2`	fixed
Alpine	squid	3.4	`3.5.27-r0`	fixed
Alpine	squid	3.5	`3.5.27-r0`	fixed
Alpine	squid	3.6	`3.5.27-r0`	fixed
Alpine	squid	3.7	`3.5.27-r0`	fixed
Alpine	squid	3.8	`3.5.27-r2`	fixed
Alpine	squid	3.9	`3.5.27-r2`	fixed
Ubuntu	squid3	14.04	`3.3.8-1ubuntu3`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu4`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu5`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.1`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.2`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.3`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.4`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.6`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.8`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.9`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.10`	vulnerable
Ubuntu	squid3	14.04	`3.3.8-1ubuntu6.11`	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`	fixed
Ubuntu	squid3	18.04	`3.5.23-5ubuntu1`	vulnerable
Ubuntu	squid3	18.04	`3.5.23-5ubuntu2`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	squid	source	sid	`4.1-1`	not yet assigned	Not reported	Not reported
Debian	squid	source	forky	`4.1-1`	not yet assigned	Not reported	Not reported
Debian	squid	source	trixie	`4.1-1`	not yet assigned	Not reported	Not reported
Debian	squid	source	bookworm	`4.1-1`	not yet assigned	Not reported	Not reported
Alpine	squid	apk	3.10	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.11	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.12	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.13	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.14	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.15	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.16	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.17	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.18	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.19	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.20	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.21	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.22	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.23	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.24	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.4	`3.5.27-r0`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.5	`3.5.27-r0`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.6	`3.5.27-r0`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.7	`3.5.27-r0`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.8	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Alpine	squid	apk	3.9	`3.5.27-r2`	Not reported	ALPINE-CVE-2018-1000027	Not reported
Ubuntu	squid3	deb	14.04	`3.3.8-1ubuntu6.11`	Not reported	UBUNTU-CVE-2018-1000027	Not reported
Ubuntu	squid3	deb	16.04	`3.5.12-1ubuntu7.5`	Not reported	UBUNTU-CVE-2018-1000027	Not reported
Ubuntu	squid3	deb	18.04	`3.5.23-5ubuntu2`	Not reported	UBUNTU-CVE-2018-1000027	Not reported

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: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squidclient]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-common]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · all · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · all · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 5.7-2+deb12u5 · amd64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u5 · arm64 · bookworm
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · amd64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12
- 5.7-2+deb12u6 · arm64 · bookworm-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · bookworm; dsa · squid · debian · 12

[Debian 13 (Trixie)]

[squid]Unknown
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
[squid-cgi]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
[squidclient]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
[squid-common]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · all · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
[squid-openssl]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
[squid-purge]Unknown
Source package: [squid]
Details (4)
- 6.13-2+deb13u2 · amd64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · amd64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13
- 6.13-2+deb13u2 · arm64 · trixie-security
  Fixed · Fixed: 4.1-1
  dsa · squid · debian · 13

Observed: Oct 23, 2026, 5:32:17 PM UTC

References

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