CVE-2026-54411: Linux-PAM through 1.7.2 contains an observable timing discrepancy (CWE-208) in the pam_userdb module's plaintext-password comparison path in modules/pam_userdb/pam_userdb.c that allows a local or network-adjacent attacker able to repeatedly drive authentication through a calling service to recover the plaintext password of a target account by measuring response-timing differences. The comparison uses strncmp() (or strncasecmp() when PAM_ICASE_ARG is set) preceded by a length-equa

CSIRTS triage

What: An observable timing discrepancy in pam_userdb allows attackers to exploit authentication processes.
Who is affected: Deployments of Linux-PAM version 1.7.2 and earlier are affected.
Urgency: This vulnerability has a medium severity with a CVSS score of 5.9, indicating a need for remediation.
Action: Upgrade to a version of Linux-PAM later than 1.7.2 to mitigate this vulnerability.

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EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Low exploitation riskCVE-2026-544110.32% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 24% of all scored CVEs.

CVE	CSIRTS overview	External
CVE-2026-54411	coverage & exploitation status	NVD · CVE.org