Vulnerability · Published May 12, 2026 · Assigned by GitHub_M

CVE-2026-43916pam_authnft: Heap buffer overflow in NETLINK_SOCK_DIAG reply walker

High 8.7

In plain English

A high-severity out-of-bounds read in pam_authnft from identd-ng. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).

Severity (CVSS 4.0)8.7High

Exploit odds (30 days)0.3%top 81.8% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

pam_authnft is a PAM session module binding nftables firewall rules to authenticated sessions via cgroupv2 inodes. Prior to 0.2.0-alpha, a heap buffer over-read in peer_lookup_tcp (src/peer_lookup.c:134, prior to the fix) allowed a crafted NETLINK_SOCK_DIAG reply to slip past the message-size check, then dereference past the end of the allocation. This vulnerability is fixed in 0.2.0-alpha.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Ubuntu:22.04:LTS	pam	no fix listed	UBUNTU-CVE-2026-43916
Ubuntu:24.04:LTS	pam	no fix listed	UBUNTU-CVE-2026-43916
Ubuntu:25.10	pam	no fix listed	UBUNTU-CVE-2026-43916
Ubuntu:26.04	pam	no fix listed	UBUNTU-CVE-2026-43916

Affected products (as reported)

Vendor	Product	Versions
identd-ng	pam_authnft	< 0.2.0-alpha

Weakness: CWE-125, CWE-191 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

https://github.com/identd-ng/pam_authnft/security/advisories/GHSA-5jj5-hm34-78vh x_refsource_CONFIRM
https://github.com/identd-ng/pam_authnft/pull/10 x_refsource_MISC