Bug 2479772 (CVE-2026-5947)

Summary: CVE-2026-5947 bind: SIG(0) validation during query flood may lead to undefined behavior
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in BIND. A remote attacker could exploit a race condition during SIG(0) signature validation of an incoming DNS message. If the "recursive-clients" limit is reached and the message is discarded, a use-after-free vulnerability may occur. This could lead to undefined behavior and potentially result in a denial of service.
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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: 2481347, 2481349    
Bug Blocks:    

Description OSIDB Bzimport 2026-05-19 10:01:00 UTC 
Undefined behavior may result due to a race condition leading to a use-after-free violation. If BIND receives an incoming DNS message signed with SIG(0), it begins work to validate that signature. If, during that validation, the "recursive-clients" limit is reached (as would occur during a query flood), and that same DNS message is discarded per the limit, there is a brief window of time while the SIG(0) validation may attempt to read the now-discarded DNS message.