Linux-PAM pam_userdb Observable Timing Discrepancy in Plaintext Password Comparison (CVE-2026-54411) | HOL Guard CVE

Medium · CVSS 5.9CVE-2026-54411

Linux-PAM pam_userdb Observable Timing Discrepancy in Plaintext Password Comparison

Answer in brief

CVE-2026-54411 records a Medium severity (CVSS 5.9) vulnerability in Linux-PAM pam_userdb Observable Timing Discrepancy in Plaintext Password Comparison. The current sources do not mark it as known exploited. The current feed maps Linux-PAM/Linux-PAM (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jun 14, 2026Updated Aug 10, 2026Source checked Sep 21, 2026First seen by HOL Aug 5, 2026Material review Aug 10, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.9
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux-PAM/Linux-PAM (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux-PAM/Linux-PAMgeneric	0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux-PAM/Linux-PAM.
Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

Published upstream
Jun 14, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 10, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 5, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.