Heap-based buffer overflow in Squid - CVE-2026-50012
Published: June 24, 2026
Vulnerability identifier: #VU135131
CSH Severity: Low
CVSS v4: 7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:N/VI:L/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-50012
CWE-ID: CWE-122
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote user to cause a denial of service and modify memory.
The vulnerability exists due to heap-based buffer overflow in cache_digest reply handling when processing maliciously crafted replies to cache_digest request messages. A remote privileged user can send a specially crafted reply to cause a denial of service and modify memory.
Only instances compiled with the --enable-cache-digests option are vulnerable, and exploitation requires a trusted peer relationship over TCP.
Affected software
Squid
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
Debian Linux
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Real Time 15
Server Applications Module
openSUSE Leap
Ubuntu
openEuler
Fedora
squid (Ubuntu package)
squid-openssl (Ubuntu package)
squid
squid-debuginfo
squid-debugsource
squid (Debian package)
SUSE Linux Enterprise Server 15 SP4
SUSE Linux Enterprise Server 15 SP6
SUSE Linux Enterprise Server 15 SP5
Debian Linux
SUSE Linux Enterprise Server 15
SUSE Linux Enterprise High Performance Computing LTSS 15
SUSE Linux Enterprise High Performance Computing ESPOS 15
SUSE Linux Enterprise High Performance Computing 15
SUSE Linux Enterprise Server for SAP Applications 15
SUSE Linux Enterprise Real Time 15
Server Applications Module
openSUSE Leap
Ubuntu
openEuler
Fedora
squid (Ubuntu package)
squid-openssl (Ubuntu package)
squid
squid-debuginfo
squid-debugsource
squid (Debian package)
How to mitigate CVE-2026-50012
Install security update from vendor's website.
Squid - update to 7.6
squid (Ubuntu package) - addressed in versions 3.5.12-1ubuntu7.16+esm7, 3.5.27-1ubuntu1.14+esm6, 4.10-1ubuntu1.13+esm3, 5.9-0ubuntu0.22.04.7, 5.9-0ubuntu0.22.04.8, 6.14-0ubuntu0.24.04.4, 6.14-0ubuntu0.24.04.5, 6.14-0ubuntu0.25.10.4, 7.2-2ubuntu2.2
squid-openssl (Ubuntu package) - addressed in versions 5.9-0ubuntu0.22.04.8, 6.14-0ubuntu0.24.04.5
squid - update to 4.9-31
squid-debuginfo - update to 4.9-31
squid-debugsource - update to 4.9-31
squid-debugsource - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid-debuginfo - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid - update to 7.6-1.fc44
squid (Debian package) - update to 6.13-2+deb13u2
squid (Ubuntu package) - addressed in versions 3.5.12-1ubuntu7.16+esm7, 3.5.27-1ubuntu1.14+esm6, 4.10-1ubuntu1.13+esm3, 5.9-0ubuntu0.22.04.7, 5.9-0ubuntu0.22.04.8, 6.14-0ubuntu0.24.04.4, 6.14-0ubuntu0.24.04.5, 6.14-0ubuntu0.25.10.4, 7.2-2ubuntu2.2
squid-openssl (Ubuntu package) - addressed in versions 5.9-0ubuntu0.22.04.8, 6.14-0ubuntu0.24.04.5
squid - update to 4.9-31
squid-debuginfo - update to 4.9-31
squid-debugsource - update to 4.9-31
squid-debugsource - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid-debuginfo - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid - addressed in versions 5.7-150400.3.41.1, 6.14-150600.3.20.1
squid - update to 7.6-1.fc44
squid (Debian package) - update to 6.13-2+deb13u2