CVE-2026-6669
Unbounded SCRAM iteration count causes CPU exhaustion in PgBouncer
Description
Missing upper bound on the key derivation iteration count accepted during SCRAM authentication to a backend server in PgBouncer through 1.25.2 allows a malicious or compromised PostgreSQL backend to cause uncontrolled CPU consumption in PgBouncer. The resulting key derivation cannot be interrupted in frontend builds such as PgBouncer. Because PgBouncer serves all clients from a single process, one backend can in this way stop it from serving traffic for every other database and client it is pooling, so the failure of a single backend is not contained.
INFO
Published Date :
Sept. 23, 2026, 5:17 p.m.
Last Modified :
Sept. 23, 2026, 7:40 p.m.
Remotely Exploit :
No
Source :
f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 | ||||
| CVSS 3.1 | MEDIUM | MITRE-CVE |
Solution
- Update PgBouncer to version 1.26.0 or later.
- Configure a reasonable iteration count limit.
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-2026-6669.
| URL | Resource |
|---|---|
| https://www.pgbouncer.org/changelog.html |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6669 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-2026-6669
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-2026-6669 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6669 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.
-
New CVE Received by f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
Sep. 23, 2026
Action Type Old Value New Value Added Description Missing upper bound on the key derivation iteration count accepted during SCRAM authentication to a backend server in PgBouncer through 1.25.2 allows a malicious or compromised PostgreSQL backend to cause uncontrolled CPU consumption in PgBouncer. The resulting key derivation cannot be interrupted in frontend builds such as PgBouncer. Because PgBouncer serves all clients from a single process, one backend can in this way stop it from serving traffic for every other database and client it is pooling, so the failure of a single backend is not contained. Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-400 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/6xxx/CVE-2026-6669.json">CVE-2026-6669</a> Added Reference https://www.pgbouncer.org/changelog.html -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-6669', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-23T16:33:29.069636Z'}