Bug 2381418 (CVE-2025-40777)

Summary: CVE-2025-40777 bind: bind assertion failure
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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An assertion failure flaw has been discovered in bind. If a `named` caching resolver is configured with `serve-stale-enable`: `yes`, and with `stale-answer-client-timeout` set to `0`, and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2381492, 2381493, 2381494, 2381495    
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Description OSIDB Bzimport 2025-07-16 18:01:19 UTC
If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure.
This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.