Bug 2536324

Summary: [Minor Incident] CVE-2026-81642 unbound: Unbound: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY [fedora-all]
Product: [Fedora] Fedora Reporter: Robb Gatica <rgatica>
Component: unboundAssignee: Paul Wouters <paul.wouters>
Status: NEW --- QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: urgent Docs Contact:
Priority: urgent    
Version: rawhideCC: dns-sig, minfrin, paul.wouters, pemensik, pj.pandit, tkorbar
Target Milestone: ---Keywords: Security, SecurityTracking
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["ac8a7edd-68f6-4a80-ac74-c40fe0f03ef2"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On:    
Bug Blocks: 2535059    

Description Robb Gatica 2026-09-17 17:22:39 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.

In NLnet Labs Unbound up to and including 1.26.0, a vulnerability was found in the DNSSEC validator that enables denial of service and possible remote code execution as a result of digesting DNSKEYs. A DNSKEY with an owner compression pointer to its own RDATA can overflow the digest buffer. Remote code execution is possible through attacker controlled data. An adversary can exploit the vulnerability by controlling a malicious zone and querying a vulnerable Unbound.