CVE-2019-12522

An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child...

4.5 Medium

An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child processes as a lesser user, by default the user nobody. This is done via the leave_suid call. leave_suid leaves the Saved UID as 0. This makes it trivial for an attacker who has compromised the child process to escalate their privileges back to root.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: High
Privileges needed: Low
User interaction: None

What an attacker can affect

Confidentiality: Low
Integrity: Low
Availability: Low

Exploit likelihood

0.34%Down 0.3 points since Apr 14, 2021

What each source reports

NVD Score used 4.5

Record: CVE-2019-12522
CVSS 3.1: 4.5 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
CVSS 2.0: 4.4 MediumAV:L/AC:M/Au:N/C:P/I:P/A:P
Weakness: CWE-269
Updated: 2026-11-02

CVE List No score

Record: CVE-2019-12522
Updated: 2026-11-02

EUVDEUVD-2019-4117 No score

Record: EUVD-2019-4117
Updated: 2026-11-03

GitHub AdvisoriesGHSA-rwjf-j42w-jfr4 No score

An issue was discovered in Squid through 4.7. When Squid is run as root, it spawns its child...

Record: GHSA-rwjf-j42w-jfr4
Weakness: CWE-269
Updated: 2026-11-02

OSV 4.5

Record: CVE-2019-12522
CVSS 3.1: 4.5 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-02

OSVDEBIAN-CVE-2019-12522 4.5

Record: DEBIAN-CVE-2019-12522
CVSS 3.1: 4.5 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-02

OSVUBUNTU-CVE-2019-12522 4.5

Record: UBUNTU-CVE-2019-12522
CVSS 3.1: 4.5 MediumCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Updated: 2026-11-06

Affected products

squid-cache squid

Affected packages

Affected packages
Package	Affected	Fixed
`squid` Debian:12	All versions, plus listed versions 5.7-25.7-2+deb12u15.7-2+deb12u25.7-2+deb12u35.7-2+deb12u4 Show 21 moreShow less 5.7-2+deb12u55.7-2+deb12u66.1-16.1-26.10-16.12-16.13-16.13-26.3-16.5-16.6-16.8-16.9-17.1-17.2-17.2-27.4-17.5-17.6-17.6-27.7-1	None known
`squid` Debian:13	All versions, plus listed versions 6.13-26.13-2+deb13u16.13-2+deb13u26.13-2+deb13u37.1-1 Show 7 moreShow less 7.2-17.2-27.4-17.5-17.6-17.6-27.7-1	None known
`squid` Debian:14	All versions, plus listed versions 6.13-27.1-17.2-17.2-27.4-1 Show 4 moreShow less 7.5-17.6-17.6-27.7-1	None known
`squid3` Ubuntu:Pro:16.04:LTS	All versions, plus listed versions 3.3.8-1ubuntu163.3.8-1ubuntu173.5.12-1ubuntu63.5.12-1ubuntu73.5.12-1ubuntu7.1 Show 22 moreShow less 3.5.12-1ubuntu7.23.5.12-1ubuntu7.33.5.12-1ubuntu7.43.5.12-1ubuntu7.53.5.12-1ubuntu7.63.5.12-1ubuntu7.73.5.12-1ubuntu7.83.5.12-1ubuntu7.93.5.12-1ubuntu7.103.5.12-1ubuntu7.113.5.12-1ubuntu7.123.5.12-1ubuntu7.133.5.12-1ubuntu7.143.5.12-1ubuntu7.153.5.12-1ubuntu7.163.5.12-1ubuntu7.16+esm13.5.12-1ubuntu7.16+esm23.5.12-1ubuntu7.16+esm33.5.12-1ubuntu7.16+esm43.5.12-1ubuntu7.16+esm53.5.12-1ubuntu7.16+esm63.5.12-1ubuntu7.16+esm7	None known
`squid3` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 3.5.23-5ubuntu13.5.23-5ubuntu23.5.27-1ubuntu13.5.27-1ubuntu1.13.5.27-1ubuntu1.2 Show 18 moreShow less 3.5.27-1ubuntu1.33.5.27-1ubuntu1.43.5.27-1ubuntu1.53.5.27-1ubuntu1.63.5.27-1ubuntu1.73.5.27-1ubuntu1.83.5.27-1ubuntu1.93.5.27-1ubuntu1.103.5.27-1ubuntu1.113.5.27-1ubuntu1.123.5.27-1ubuntu1.133.5.27-1ubuntu1.143.5.27-1ubuntu1.14+esm13.5.27-1ubuntu1.14+esm23.5.27-1ubuntu1.14+esm33.5.27-1ubuntu1.14+esm43.5.27-1ubuntu1.14+esm53.5.27-1ubuntu1.14+esm6	None known
`squid` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 4.8-1ubuntu24.8-1ubuntu34.9-2ubuntu14.9-2ubuntu24.9-2ubuntu3 Show 18 moreShow less 4.9-2ubuntu44.10-1ubuntu14.10-1ubuntu1.14.10-1ubuntu1.24.10-1ubuntu1.34.10-1ubuntu1.44.10-1ubuntu1.54.10-1ubuntu1.64.10-1ubuntu1.74.10-1ubuntu1.84.10-1ubuntu1.94.10-1ubuntu1.104.10-1ubuntu1.114.10-1ubuntu1.124.10-1ubuntu1.134.10-1ubuntu1.13+esm14.10-1ubuntu1.13+esm24.10-1ubuntu1.13+esm3	None known
`squid` Ubuntu:22.04:LTS	All versions, plus listed versions 4.13-10ubuntu55.2-1ubuntu15.2-1ubuntu35.2-1ubuntu45.2-1ubuntu4.1 Show 13 moreShow less 5.2-1ubuntu4.25.2-1ubuntu4.35.7-0ubuntu0.22.04.15.7-0ubuntu0.22.04.25.7-0ubuntu0.22.04.35.7-0ubuntu0.22.04.45.9-0ubuntu0.22.04.15.9-0ubuntu0.22.04.25.9-0ubuntu0.22.04.35.9-0ubuntu0.22.04.45.9-0ubuntu0.22.04.55.9-0ubuntu0.22.04.75.9-0ubuntu0.22.04.8	None known
`squid` Ubuntu:24.04:LTS	All versions, plus listed versions 6.1-2ubuntu16.1-2ubuntu26.5-1ubuntu16.5-1ubuntu26.5-1ubuntu3 Show 11 moreShow less 6.6-1ubuntu46.6-1ubuntu56.6-1ubuntu5.16.10-0ubuntu0.24.04.16.13-0ubuntu0.24.04.16.13-0ubuntu0.24.04.26.13-0ubuntu0.24.04.36.14-0ubuntu0.24.04.16.14-0ubuntu0.24.04.26.14-0ubuntu0.24.04.46.14-0ubuntu0.24.04.5	None known
`squid` Ubuntu:25.10	All versions, plus listed versions 6.13-1ubuntu16.13-1ubuntu26.13-1ubuntu36.13-1ubuntu46.13-1ubuntu4.16.14-0ubuntu0.25.10.16.14-0ubuntu0.25.10.26.14-0ubuntu0.25.10.4	None known
`squid` Ubuntu:26.10	All versions, plus listed versions 7.2-2ubuntu27.6-2ubuntu17.6-2ubuntu37.7-1ubuntu1	None known
`squid` Ubuntu:26.04:LTS	All versions, plus listed versions 6.13-1ubuntu46.13-1ubuntu57.2-2ubuntu17.2-2ubuntu27.2-2ubuntu2.27.7-0ubuntu0.26.04.17.7-0ubuntu0.26.04.2	None known

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected, facts	OSV
Nov 3, 2026	aliases	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2019-12522 is a medium vulnerability (CVSS 4.5) in Squid-cache Squid, published April 15, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.34%, the 28th percentile. No source names a fixed version.