CVE-2026-54411
Summary
| CVE | CVE-2026-54411 |
|---|---|
| State | PUBLISHED |
| Assigner | TuranSec |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-14 18:17:20 UTC |
| Updated | 2026-06-14 18:17:20 UTC |
| 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. The comparison uses strncmp() (or strncasecmp() when PAM_ICASE_ARG is set) preceded by a length-equality check, so the time to reject a candidate depends on the index of the first differing byte and on whether the candidate's length matches the stored password, leaking the password length and individual prefix bytes. The vulnerable path is reached when the administrator configures pam_userdb with crypt=none, with an unrecognized crypt method, or without a crypt= argument, causing the module to store and compare credentials in plaintext. |
Risk And Classification
Primary CVSS: v4.0 6.9 MEDIUM from 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
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/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:N/R:X/V:D/RE:X/U:X
Problem Types: CWE-208 | CWE-208 CWE-208 Observable Timing Discrepancy
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | Secondary | 6.9 | MEDIUM | 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/C... |
| 4.0 | CNA | CVSS | 6.9 | MEDIUM | 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/A... |
| 3.1 | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | Secondary | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| 3.1 | CNA | CVSS | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
CVSS v4.0 Breakdown
Attack Vector
NetworkAttack Complexity
HighAttack Requirements
PresentPrivileges Required
NoneUser Interaction
NoneConfidentiality
HighIntegrity
NoneAvailability
NoneSub Conf.
NoneSub Integrity
NoneSub Availability
NoneCVSS: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/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:N/R:X/V:D/RE:X/U:X
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/linux-pam/linux-pam/blob/master/libpam/include/pam_inline.h | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | github.com | |
| cwe.mitre.org/data/definitions/208.html | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | cwe.mitre.org | |
| github.com/linux-pam/linux-pam | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | github.com | |
| github.com/linux-pam/linux-pam/blob/master/modules/pam_userdb/pam_userdb.c | 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c | github.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Xurshidbek Sobirjonov (en)
There are currently no legacy QID mappings associated with this CVE.