USN-9065-1: GNU C Library vulnerabilities

Published Nov 12, 2026
·
Updated

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)

Affected Software

8 affected componentsFixes available
All of the following
ubuntu/libc6<2.44-1ubuntu2.1
2.44-1ubuntu2.1
Ubuntu Ubuntu=26.10
All of the following
ubuntu/libc6<2.43-2ubuntu2.7
2.43-2ubuntu2.7
Ubuntu Ubuntu=26.04
All of the following
ubuntu/libc6<2.39-0ubuntu8.12
2.39-0ubuntu8.12
Ubuntu Ubuntu=24.04
All of the following
ubuntu/libc6<2.35-0ubuntu3.18
2.35-0ubuntu3.18
Ubuntu Ubuntu=22.04

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade ubuntu/libc6 to a version that resolves this vulnerability.

    Fixed in 2.44-1ubuntu2.1
  2. Upgrade

    Upgrade ubuntu/libc6 to a version that resolves this vulnerability.

    Fixed in 2.43-2ubuntu2.7
  3. Upgrade

    Upgrade ubuntu/libc6 to a version that resolves this vulnerability.

    Fixed in 2.39-0ubuntu8.12
  4. Upgrade

    Upgrade ubuntu/libc6 to a version that resolves this vulnerability.

    Fixed in 2.35-0ubuntu3.18
  5. Upgrade

    Upgrade GNU C Library to a version that resolves this vulnerability.

    Patch USN-9065-1

Event History

Nov 12, 2026
Advisory Published
via Ubuntu·12:00 AM
Data Sourced
via Ubuntu·12:00 AM
DescriptionAffected Software

Frequently Asked Questions

1

Which issues described here require an attacker to have local access?

CVE-2026-86805 and CVE-2026-95818 are described as locally exploitable. CVE-2026-86805 could allow elevated-privilege code execution in setuid or setgid programs, while CVE-2026-95818 could cause a crash or disclose sensitive information.

2

Is any issue exploitable by an attacker on the local network?

Yes. CVE-2026-8674 involves long domain names in DNS search lists and could be used by an attacker on the local network to crash GNU C Library, causing denial of service.

3

Which issue has the most severe stated impact?

CVE-2026-18374 could cause GNU C Library to crash or allow arbitrary code execution. CVE-2026-86805 could allow a local attacker to execute arbitrary code with elevated privileges.

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