CVE-2026-43916: pam_authnft: Heap buffer overflow in NETLINK_SOCK_DIAG reply walker
Vulnerability summary
CVE-2026-43916 is a high (CVSS 8.7) Out-of-bounds Read vulnerability in identd-ng pam_authnft. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 18.1% of scored vulnerabilities.
Severe, CVSS 8.7 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Timeline
- 12-05-2026PublishedVulnerability first disclosed.
- 13-05-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
3 scores · 3 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- NVDNIST8.7HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS trend
Probability
0.26%
Chance of exploitation in the next 30 days
Percentile
18%
Versus all other CVEs
30-day change
Decrease -0.18 pp
From 0.45% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-125Out-of-bounds ReadThe product reads data past the end, or before the beginning, of the intended buffer.
- CWE-191Integer Underflow (Wrap or Wraparound)The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.
Affected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Identd-ng1 product
- pam_authnft< 0.2.0-alpha
Ubuntu1 product
- pamAll versions (No fix recorded)
2 vendors · 2 products
References
4 links- github.com/identd-ng/pam_authnft/security/advisories/GHSA-5jj5-hm34-78vhX Refsource CONFIRM
- github.com/identd-ng/pam_authnft/pull/10X Refsource MISC