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Fencer Vulns
medium 5.9

CVE-2026-6669 json

Unbounded SCRAM iteration count causes CPU exhaustion in PgBouncer

published 2026-09-23 46 d ago modified 2026-10-01 38 d ago also BIT-pgbouncer-2026-6669 , EUVD-2026-85364

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami pgbouncer 1.26.0
  • pgbouncer pgbouncer 1.26.0
  • pgbouncer Debian 14 1.26.0-1

debian advisories DEBIAN-CVE-2026-6669

  • pgbouncer hummingbird 1 1.26.0-0.1.hum1

red hat advisories RHSA-2026:70698

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-6669 updated cvss 5.9

pgbouncer: PgBouncer: Denial of Service via unbounded SCRAM iteration count

  • Red Hat Hardened Images pgbouncer 1.26.0-0.1.hum1
    fixed: vendor fix RHSA-2026:70698

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
46 d ago

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
bitnami pgbouncer
<1.26.0
1.26.0

Affected products

  • n/a PgBouncer

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.