Process-memory corruption via unchecked SCRAM message length
Published May 9, 2026 · Updated May 9, 2026
Stack-based buffer overflow in PgBouncer before 1.25.2 allows remote attackers controlling a backend to corrupt process memory via a long SCRAM nonce. build_client_final_message() appends ",p=" to a fixed-size stack buffer but fails to reject a strlcat() return value that is at least the buffer size before encoding the client proof. Reachability requires PgBouncer to initiate SCRAM authentication to an attacker-controlled PostgreSQL backend; the documented consequence is stack corruption, and no public source specifies whether code execution was demonstrated.
Summary
What happened
Stack-based buffer overflow in PgBouncer before 1.25.2 allows remote attackers controlling a backend to corrupt process memory via a long SCRAM nonce. build_client_final_message() appends ",p=" to a fixed-size stack buffer but fails to reject a strlcat() return value that is at least the buffer size before encoding the client proof. Reachability requires PgBouncer to initiate SCRAM authentication to an attacker-controlled PostgreSQL backend; the documented consequence is stack corruption, and no public source specifies whether code execution was demonstrated.
The record
- CVE
- CVE-2026-6665
- Published
- May 9, 2026
- Updated
- May 9, 2026
- Vendor
- PgBouncer
- Product
- PgBouncer
- Classifications
- CWE-121
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 9, 2026CVE publishedPublication date reported by the CVE source.
- May 9, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <1.25.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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