Vulnerability · Published May 9, 2026 · Assigned by PostgreSQL
CVE-2026-6665PgBouncer buffer overflow in SCRAM
High 8.1
In plain English
A high-severity stack buffer overflow in PgBouncer. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.4%top 68.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
The SCRAM code in PgBouncer before 1.25.2 did not check the return value of strlcat() correctly when building the contents of the SCRAM client-final-message. A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | pgbouncer | no fix listed | DEBIAN-CVE-2026-6665 |
| Debian:13 | pgbouncer | 1.24.1-1+deb13u2 | DEBIAN-CVE-2026-6665 |
| Debian:14 | pgbouncer | 1.25.2-1 | DEBIAN-CVE-2026-6665 |
| Ubuntu:22.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6665 |
| Ubuntu:24.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6665 |
| Ubuntu:25.10 | pgbouncer | no fix listed | UBUNTU-CVE-2026-6665 |
| Ubuntu:26.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6665 |
| Ubuntu:26.10 | pgbouncer | no fix listed | UBUNTU-CVE-2026-6665 |
Affected products (as reported)
Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H