Bug 2507651

Summary: CVE-2026-32665 unbound: Unbound: Denial of Service via improper validation of DNS-over-QUIC client length [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": ["69acf7a6-19bc-482d-8ba9-47e3b2d80470"]}
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 01:17:19 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: 2503060    

Description Marco Benatto 2026-07-27 20:03:53 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.

When downstream DNS-over-QUIC (DoQ) is enabled, Unbound documents the 'quic-size' configuration option as the maximum number of bytes for all QUIC buffers and data combined, and states that new connections or streams should be refused/reset once the limit is exceeded. However, an improper validation of the client provided length could allow over allocating memory and trivially exceeding the configured budget for future DoQ connections leading to denial of service for new DoQ clients.
Comment 1 Fedora Update System 2026-07-28 10:37:49 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 10:39:03 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 01:17:19 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 01:14:53 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.