Bug 2498022 (CVE-2026-15041)

Summary: CVE-2026-15041 389-ds-base: 389-ds-base: Non-constant-time comparison in PBKDF2-SHA256 password verification
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: aadhikar, bsmejkal, jachapma, mreynolds, progier, rhel-process-autobot, snegrini, spichugi, tbordaz, vashirov, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in 389 Directory Server. The PBKDF2-SHA256 password verification function uses standard memcmp() for comparing password hashes instead of a constant-time comparison function. A remote attacker could potentially use timing measurements of LDAP bind attempts to infer partial hash information, though practical exploitation is extremely difficult due to PBKDF2 computational overhead.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2498023    
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Description OSIDB Bzimport 2026-07-08 10:02:42 UTC 
A flaw was found in 389 Directory Server. The PBKDF2-SHA256 password verification function pbkdf2_sha256_pw_cmp() in ldap/servers/plugins/pwdstorage/pbkdf2_pwd.c uses standard memcmp() for hash comparison instead of the project's constant-time slapi_ct_memcmp(). Every other password storage scheme in the same plugin uses slapi_ct_memcmp(), which was introduced specifically to prevent timing side-channels (see CVE-2016-5405). This inconsistency allows a remote attacker with network access to the LDAP service to potentially infer partial hash information through repeated timing measurements of LDAP bind attempts. Practical exploitation is extremely difficult due to the PBKDF2 work factor (8192+ iterations, ~2ms computation time) which dominates and masks the nanosecond-level memcmp timing delta.