Medium severity · published Jun 14, 2026
CVE-2026-54411
Linux-PAM pam_userdb Observable Timing Discrepancy in Plaintext Password Comparison
5.9
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Linux-PAM · Linux-PAM
through 1.7.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-54411
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-54411
cwe.mitre.org
https://cwe.mitre.org/data/definitions/208.html
github.com
https://github.com/linux-pam/linux-pam
github.com
https://github.com/linux-pam/linux-pam/blob/master/libpam/include/pam_inline.h
github.com
https://github.com/linux-pam/linux-pam/blob/master/modules/pam_userdb/pam_userdb.c#L327
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