CVE-2026-6665
A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.
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
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-121
- Affected
- pgbouncer/pgbouncer
- Source
- f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
EPSS 0.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.