CVE-2026-54411

Publication date 14 June 2026

Last updated 13 August 2026

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
pam	26.04 LTS resolute	Fixed 1.7.0-5ubuntu3.1
	25.10 questing	Ignored end of life, was needs-triage
	24.04 LTS noble	Fixed 1.5.3-5ubuntu5.6
	22.04 LTS jammy	Fixed 1.4.0-11ubuntu2.7
	20.04 LTS focal	Needs evaluation
	18.04 LTS bionic	Needs evaluation
	16.04 LTS xenial	Needs evaluation
	14.04 LTS trusty	Needs evaluation

Notes

mdeslaur

This is only an issue when pam_userdb is used with crypt set to none, which means configured to store password in plaintext in the database.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
pam	Upstream: 30708d9

Severity score breakdown

CVSS version:

Base score 6.9 · Medium

Base metrics

Parameter	Value
Attack vector	Network
Attack complexity	High
Attack requirements	Present
Privileges required	None
User interaction	None
Vulnerable system - Confidentiality impact	High
Vulnerable system - Integrity impact	None
Vulnerable system - Availability impact	None
Subsequent system - Confidentiality impact	None
Subsequent system - Integrity impact	None
Subsequent system - Availability impact	None

Scores

Parameter	Value
Base score	6.9 · Medium
Base + Threat score	-
Base + Environmental score	-
Base + Threat + Environmental score	-

Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/AU:N/V:D

Base score 5.9 · Medium