Bug 2539546 (CVE-2026-6669)

Summary: CVE-2026-6669 pgbouncer: PgBouncer: Denial of Service via unbounded SCRAM iteration count
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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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A flaw was found in PgBouncer. A malicious or compromised PostgreSQL backend can exploit a missing upper bound on the key derivation iteration count during SCRAM (Salted Challenge Response Authentication Mechanism) authentication. This can lead to uncontrolled CPU consumption in PgBouncer, effectively stopping it from serving traffic for all other databases and clients it manages. This results in a Denial of Service (DoS) for all connected services.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2539634, 2539635    
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Description OSIDB Bzimport 2026-09-23 17:03:14 UTC 
Missing upper bound on the key derivation iteration count accepted during SCRAM authentication to a backend server in PgBouncer through 1.25.2 allows a malicious or compromised PostgreSQL backend to cause uncontrolled CPU consumption in PgBouncer. The resulting key derivation cannot be interrupted in frontend builds such as PgBouncer. Because PgBouncer serves all clients from a single process, one backend can in this way stop it from serving traffic for every other database and client it is pooling, so the failure of a single backend is not contained.