SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-6665

A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.

CRITICAL 9.8EPSS 0.37%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.37% probability · 31th percentile
CISA KEV
Not listed
Weakness
CWE-121
Affected
pgbouncer/pgbouncer
Source
f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.