PT-2026-26670 · Gnu+1 · Gnu C Library+1

Kevin Farrell · CVE-2026-4437 · Published 2026-01-01 · Updated 2026-06-01

Positive Technologies (AI Summary)

CVSS v3.1

7.5

High

Base vector

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions GNU C Library versions 2.34 through 2.43

Description The GNU C Library contains a flaw where calling the gethostbyaddr or gethostbyaddr r functions with a specific nsswitch.conf configuration utilizing the library’s DNS backend may lead to a violation of the DNS specification. A crafted response from a configured DNS server could cause the application to incorrectly interpret a non-answer section of the DNS response as a valid answer.

Recommendations Versions prior to 2.34 or after 2.43 should be used.

Exploit

Fix

Out of bounds Read

Weakness Enumeration

CWE-125

Related Identifiers

ALSA-2026:19061

ALSA-2026:20597

CVE-2026-4437

ECHO-3C7D-5484-9E80

OPENSUSE-SU-2026:10662-1

OPENSUSE-SU-2026:20501-1

RHSA-2026:19061

RHSA-2026:20597

RHSA-2026:7316

SUSE-SU-2026:1369-1

SUSE-SU-2026:20999-1

SUSE-SU-2026:21019-1

SUSE-SU-2026:21039-1

SUSE-SU-2026:21069-1

SUSE-SU-2026:21164-1

Affected Products

Gnu C Library

Rocky Linux

References · 55

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/4xxx/CVE-2026-4437.json · Exploit
• https://osv.dev/vulnerability/BELL-CVE-2026-4437 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:21019-1 · Vendor Advisory
• https://sourceware.org/bugzilla/show_bug.cgi?id=34014 · Patch
• https://osv.dev/vulnerability/SUSE-SU-2026:21164-1 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-DEBIAN-12-CVE-2026-4437 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2404-CVE-2026-4437 · Vendor Advisory
• https://osv.dev/vulnerability/SUSE-SU-2026:21069-1 · Vendor Advisory
• https://errata.almalinux.org/9/ALSA-2026-20597.html · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-4437 · Vendor Advisory
• https://errata.rockylinux.org/RLSA-2026:20597 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2204-CVE-2026-4437 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:20501-1 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2026-4437 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-4437 · Security Note