Bug 2463398

Summary: CVE-2026-40355 krb5: MIT Kerberos 5: Denial of Service via NULL pointer dereference in NegoEx mechanism [fedora-all]
Product: [Fedora] Fedora Reporter: Sandipan Roy <saroy>
Component: krb5Assignee: Julien Rische <jrische>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: medium    
Version: rawhideCC: abokovoy, antorres, ftrivino, jrische, j, sbose, ssorce
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["c3dca2aa-6ff7-418a-b366-601acb3a949f"]}
Fixed In Version: krb5-1.22.2-7.fc45 krb5-1.22.2-4.fc44 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-04-29 15:53:59 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: 2463370    

Description Sandipan Roy 2026-04-28 08:50:06 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.

Comment 1 Fedora Update System 2026-04-29 13:05:59 UTC
FEDORA-2026-2e9fe57a46 (krb5-1.22.2-7.fc45) has been submitted as an update to Fedora 45.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-2e9fe57a46

Comment 2 Fedora Update System 2026-04-29 13:43:07 UTC
FEDORA-2026-8b43ea2f82 (krb5-1.22.2-4.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-8b43ea2f82

Comment 3 Fedora Update System 2026-04-29 13:44:37 UTC
FEDORA-2026-684396998a (krb5-1.22.2-4.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-684396998a

Comment 4 Fedora Update System 2026-04-29 14:45:15 UTC
FEDORA-2026-6c99aaa6d3 (krb5-1.21.3-7.fc42) has been submitted as an update to Fedora 42.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-6c99aaa6d3

Comment 5 Fedora Update System 2026-04-29 15:53:59 UTC
FEDORA-2026-2e9fe57a46 (krb5-1.22.2-7.fc45) has been pushed to the Fedora 45 stable repository.
If problem still persists, please make note of it in this bug report.

Comment 6 Fedora Update System 2026-04-30 02:15:32 UTC
FEDORA-2026-684396998a 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-2026-684396998a`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-684396998a

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

Comment 7 Fedora Update System 2026-04-30 02:33:49 UTC
FEDORA-2026-8b43ea2f82 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-2026-8b43ea2f82`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-8b43ea2f82

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

Comment 8 Fedora Update System 2026-04-30 02:49:37 UTC
FEDORA-2026-6c99aaa6d3 has been pushed to the Fedora 42 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2026-6c99aaa6d3`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2026-6c99aaa6d3

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

Comment 9 Fedora Update System 2026-05-02 02:11:33 UTC
FEDORA-2026-8b43ea2f82 (krb5-1.22.2-4.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.