What is CVE-2026-6665?

CVE-2026-6665 is a high-severity vulnerability in Pgbouncer, classified under Stack-based Buffer Overflow. CVSS score: 8.1/10. Published 2026-05-09.

How severe is CVE-2026-6665?

High severity. CVSS v3 base score is 8.1 out of 10.

Buffer overflow in Pgbouncer

CVE-2026-6665

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…

Vulnerability class: Buffer Overflow

EPSS: 0.000 (5.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Pgbouncer
N/a Pgbouncer — versions 0

Weakness classification (CWE)

CWE-121 — Stack-based Buffer Overflow

References

f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 (Release Notes)

Frequently asked questions

What is CVE-2026-6665?: CVE-2026-6665 is a high-severity vulnerability in Pgbouncer, classified under Stack-based Buffer Overflow. CVSS score: 8.1/10. Published 2026-05-09.
How severe is CVE-2026-6665?: High severity. CVSS v3 base score is 8.1 out of 10.