Bug 2498023

Summary: CVE-2026-15041 389-ds-base: 389-ds-base: Non-constant-time comparison in PBKDF2-SHA256 password verification [fedora-all]
Product: [Fedora] Fedora Reporter: Samuele Negrini <snegrini>
Component: 389-ds-baseAssignee: Viktor Ashirov <vashirov>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: low Docs Contact:
Priority: low    
Version: rawhideCC: abokovoy, jachapma, mreynolds, spichugi, tbordaz, vashirov
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---Flags: fedora-admin-xmlrpc: mirror+
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["de4fadec-ed8c-4f57-9b38-155538269574"]}
Fixed In Version: 389-ds-base-3.3.1-3.fc45 389-ds-base-3.1.5-4.fc43 389-ds-base-3.2.3-5.fc44 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-09-25 00:16:28 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 2498022    

Description Samuele Negrini 2026-07-08 10:11:05 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

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.

Comment 1 Aoife Moloney 2026-08-17 15:15:46 UTC
This bug appears to have been reported against 'rawhide' during the Fedora Linux 45 development cycle.
Changing version to 45.

Comment 2 Viktor Ashirov 2026-09-07 18:58:59 UTC
Fixed in https://github.com/389ds/389-ds-base/commit/293b88c91

Comment 3 Fedora Update System 2026-09-07 21:24:22 UTC
FEDORA-2026-b16c9cbc0f (389-ds-base-3.2.3-2.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

Comment 4 Fedora Update System 2026-09-08 01:38:31 UTC
FEDORA-2026-c1e25a4642 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-c1e25a4642`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-c1e25a4642

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 5 Fedora Update System 2026-09-08 01:58:24 UTC
FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 6 Fedora Update System 2026-09-08 02:20:49 UTC
FEDORA-2026-0b8bc362b1 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0b8bc362b1`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0b8bc362b1

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 7 Fedora Update System 2026-09-09 05:04:25 UTC
FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 8 Fedora Update System 2026-09-10 01:46:34 UTC
FEDORA-2026-b16c9cbc0f has been pushed to the Fedora 44 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-b16c9cbc0f`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-b16c9cbc0f

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 9 Fedora Update System 2026-09-10 02:06:55 UTC
FEDORA-2026-0b8bc362b1 has been pushed to the Fedora 43 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-0b8bc362b1`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-0b8bc362b1

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 10 Fedora Update System 2026-09-10 02:16:38 UTC
FEDORA-2026-c1e25a4642 has been pushed to the Fedora 45 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-c1e25a4642`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-c1e25a4642

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 11 Fedora Update System 2026-09-25 00:16:28 UTC
FEDORA-2026-c1e25a4642 (389-ds-base-3.3.1-3.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 12 Fedora Update System 2026-09-25 00:55:28 UTC
FEDORA-2026-0b8bc362b1 (389-ds-base-3.1.5-4.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 13 Fedora Update System 2026-09-25 01:12:28 UTC
FEDORA-2026-b16c9cbc0f (389-ds-base-3.2.3-5.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.