Bug 2535469 (CVE-2026-77119)

Summary: CVE-2026-77119 bind9: bind: BIND 9: DNSSEC bypass via NSEC3 insecure-referral proof
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in BIND 9. A remote attacker could exploit a vulnerability where a validly signed NSEC3 record from an unrelated DNS zone might be accepted as proof of insecurity. This could downgrade a secure delegation, allowing forged unsigned DNS answers to be accepted by the resolver, potentially leading to DNS spoofing or integrity compromise.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2535871    
Bug Blocks:    

Description OSIDB Bzimport 2026-09-16 14:34:15 UTC
A validly signed NSEC3 from an unrelated sibling zone may be accepted as an insecurity proof, downgrading a secure delegation and letting a forged unsigned answer through.
This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.