USN-9065-1: GNU C Library vulnerabilities

Publication date

12 November 2026

Overview

Several security issues were fixed in GNU C Library.


Packages

Details

It was discovered that the GNU C Library incorrectly handled the ccs=
option in the fopen function. An attacker could possibly use this issue
to cause GNU C Library to crash or execute arbitrary code.
(CVE-2026-18374)

It was discovered that the GNU C Library incorrectly handled long domain
names in DNS search lists. An attacker on the local network could
possibly use this issue to cause GNU C Library to crash, resulting in a
denial of service. (CVE-2026-8674)

It was discovered that the GNU C Library dynamic loader had a
time-of-check to time-of-use race condition when handling the $ORIGIN
path expansion in setuid or setgid programs. A local attacker could
possibly use this issue to execute arbitrary code with elevated
privileges. (CVE-2026-86805)

It was discovered that the GNU C Library dynamic loader...

It was discovered that the GNU C Library incorrectly handled the ccs=
option in the fopen function. An attacker could possibly use this issue
to cause GNU C Library to crash or execute arbitrary code.
(CVE-2026-18374)

It was discovered that the GNU C Library incorrectly handled long domain
names in DNS search lists. An attacker on the local network could
possibly use this issue to cause GNU C Library to crash, resulting in a
denial of service. (CVE-2026-8674)

It was discovered that the GNU C Library dynamic loader had a
time-of-check to time-of-use race condition when handling the $ORIGIN
path expansion in setuid or setgid programs. A local attacker could
possibly use this issue to execute arbitrary code with elevated
privileges. (CVE-2026-86805)

It was discovered that the GNU C Library dynamic loader incorrectly
handled $ORIGIN path expansion, leading to a stack-based buffer
overflow. A local attacker could possibly use this issue to cause GNU C
Library to crash, resulting in a denial of service, or obtain sensitive
information. (CVE-2026-95818)

It was discovered that the GNU C Library nscd service incorrectly
handled large DNS responses. An attacker could possibly use this issue
to cause nscd to crash, resulting in a denial of service.
(CVE-2026-89092)

It was discovered that the GNU C Library strncasecmp function optimized
for the Power8 architecture incorrectly handled certain inputs. An
attacker could possibly use this issue to cause GNU C Library to crash,
resulting in a denial of service. (CVE-2026-97399)

It was discovered that the GNU C Library incorrectly restricted path
traversal when processing the LANGUAGE environment variable in gettext.
A local attacker could possibly use this issue to load message catalogs
from arbitrary locations and execute arbitrary code.
(CVE-2026-84243)


Update instructions

In general, a standard system update will make all the necessary changes.

Learn more about how to get the fixes.

The problem can be corrected by updating your system to the following package versions:

Ubuntu Release Package Version
26.10 stonking libc6 –  2.44-1ubuntu2.1
26.04 LTS resolute libc6 –  2.43-2ubuntu2.7
24.04 LTS noble libc6 –  2.39-0ubuntu8.12
22.04 LTS jammy libc6 –  2.35-0ubuntu3.18

Reduce your security exposure

Ubuntu Pro provides ten-year security coverage to 25,000+ packages in Main and Universe repositories, and it is free for up to five machines.


Have additional questions?

Talk to a member of the team ›