Bug 2507650

Summary: CVE-2026-44690 unbound: Unbound: Cache poisoning via insufficient RRSIG.Labels validation and premature cache writes [fedora-all]
Product: [Fedora] Fedora Reporter: Marco Benatto <mbenatto>
Component: unboundAssignee: Paul Wouters <paul.wouters>
Status: CLOSED ERRATA QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: dns-sig, minfrin, paul.wouters, pemensik, pj.pandit, tkorbar
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["0ce08305-9b43-414c-9841-aa62ebdedf90"]}
Fixed In Version: unbound-1.25.2-1.fc44 unbound-1.25.2-1.fc43 Doc Type: ---
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2026-07-30 01:17:15 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: 2503063    

Description Marco Benatto 2026-07-27 20:03:43 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.

Insufficient validation of the RRSIG.Labels field combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning that permits a malicious actor controlling a single delegated zone to poison 
arbitrary sibling zones under NSEC-signed parent domains. Unbound 1.25.2 includes fixes to add lower-bound check in RRSIG labels, move cache write stricly after validation and adding bailiwick check when updating wildcards.
Comment 1 Fedora Update System 2026-07-28 10:37:45 UTC 
FEDORA-2026-3170ee6a1c (unbound-1.25.2-1.fc43) has been submitted as an update to Fedora 43.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-3170ee6a1c
Comment 2 Fedora Update System 2026-07-28 10:38:59 UTC 
FEDORA-2026-e495bd59ef (unbound-1.25.2-1.fc44) has been submitted as an update to Fedora 44.
https://bodhi.fedoraproject.org/updates/FEDORA-2026-e495bd59ef
Comment 3 Fedora Update System 2026-07-30 01:17:15 UTC 
FEDORA-2026-e495bd59ef (unbound-1.25.2-1.fc44) has been pushed to the Fedora 44 stable repository.
If problem still persists, please make note of it in this bug report.
Comment 4 Fedora Update System 2026-07-31 01:14:50 UTC 
FEDORA-2026-3170ee6a1c (unbound-1.25.2-1.fc43) has been pushed to the Fedora 43 stable repository.
If problem still persists, please make note of it in this bug report.