CVE-2026-6665
PgBouncer buffer overflow in SCRAM
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.
INFO
Published Date :
May 9, 2026, 1:16 a.m.
Last Modified :
May 14, 2026, 6:52 p.m.
Remotely Exploit :
Yes !
Source :
f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 | ||||
| CVSS 3.1 | CRITICAL | [email protected] |
Solution
- Update PgBouncer to version 1.25.2 or later.
- Apply the vendor-provided patch for SCRAM.
- Restart the PgBouncer service.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6665.
| URL | Resource |
|---|---|
| https://www.pgbouncer.org/changelog.html#pgbouncer-125x | Release Notes |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6665 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6665
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6665 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6665 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 14, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Added CPE Configuration OR *cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:* versions up to (excluding) 1.25.2 Added Reference Type PostgreSQL: https://www.pgbouncer.org/changelog.html#pgbouncer-125x Types: Release Notes -
New CVE Received by f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
May. 09, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-121 Added Reference https://www.pgbouncer.org/changelog.html#pgbouncer-125x