CVE-2026-6669
Unbounded SCRAM iteration count causes CPU exhaustion in PgBouncer
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
5.9
Unbounded SCRAM iteration count causes CPU exhaustion in PgBouncer
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.
- Record
CVE-2026-6669- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
EUVDEUVD-2026-85364
5.9
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.
- Record
EUVD-2026-85364- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-58j7-v2vx-r29w
5.9
Missing upper bound on the key derivation iteration count accepted during SCRAM authentication to...
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.
- Record
GHSA-58j7-v2vx-r29w- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
NVD
5.9
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.
- Record
CVE-2026-6669- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-400
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-6669
5.9
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.
- Record
DEBIAN-CVE-2026-6669- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVRHSA-2026:70698
7.5
Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update
- Record
RHSA-2026:70698- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-6669
5.9
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.
- Record
UBUNTU-CVE-2026-6669- CVSS 3.1
- 5.9 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVAZL-105063 No score
CVE-2026-6669 affecting package pgbouncer 1.25.2-1
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.
- Record
AZL-105063- Updated
- 2026-11-02
OSVBIT-pgbouncer-2026-6669 No score
Unbounded SCRAM iteration count causes CPU exhaustion in PgBouncer
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.
- Record
BIT-pgbouncer-2026-6669- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
pgbouncerAzure Linux:3 |
through 1.25.2-1 | None known |
pgbouncerBitnami |
before 1.26.0 | 1.26.0 |
pgbouncerDebian:12 |
All versions, plus listed versions 1.18.0-11.18.0-1+deb12u11.19.0-11.19.1-11.20.0-1 Show 19 moreShow less1.20.1-11.21.0-11.22.0-11.22.1-11.23.0-11.23.1-11.24.0-21.24.0-31.24.1-11.25.0-11.25.0-21.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-6 |
None known |
pgbouncerDebian:13 |
All versions, plus listed versions 1.24.1-11.24.1-1+deb13u11.24.1-1+deb13u21.25.0-11.25.0-2 Show 8 moreShow less1.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-6 |
None known |
pgbouncerDebian:14 |
before 1.26.0-1, plus listed versions 1.24.1-11.25.0-11.25.0-21.25.1-11.25.2-1 |
1.26.0-1 |
pgbouncerRed Hat:hummingbird:1 From an advisory covering 3 CVEs |
before 0:1.26.0-0.1.hum1 | 0:1.26.0-0.1.hum1 |
pgbouncerUbuntu:16.04:LTS |
All versions, plus listed versions 1.5.5-11.6.1-11.7-1 |
None known |
pgbouncerUbuntu:18.04:LTS |
All versions, plus listed versions 1.7.2-3build11.7.2-65-g2b8e6cf-11.8.1-11.8.1-1build1 |
None known |
pgbouncerUbuntu:20.04:LTS |
All versions, plus listed versions 1.10.0-11.10.0-1build11.11.0-11.12.0-21.12.0-3 |
None known |
pgbouncerUbuntu:22.04:LTS |
All versions, plus listed versions 1.15.0-11.16.1-1ubuntu1 |
None known |
pgbouncerUbuntu:24.04:LTS |
All versions, plus listed versions 1.20.0-11.21.0-11.22.0-11.22.0-1build11.22.0-1build31.22.0-1build4 |
None known |
pgbouncerUbuntu:26.10 |
All versions, plus listed versions 1.25.1-11.25.2-11.25.2-1ubuntu1 |
None known |
pgbouncerUbuntu:26.04:LTS |
All versions, plus listed versions 1.24.1-11.25.0-21.25.1-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-6669 is a medium vulnerability (CVSS 5.9) in pgbouncer, published September 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in pgbouncer 1.26.0.
References
pgbouncer.org/changelog.html
nvd.nist.gov/vuln/detail/CVE-2026-6669
github.com/advisories/GHSA-58j7-v2vx-r29w
security-tracker.debian.org/tracker/CVE-2026-6669
access.redhat.com/errata/RHSA-2026:70698
images.redhat.com
Show 14 moreShow less
access.redhat.com/security/cve/CVE-2026-6668
access.redhat.com/security/updates/classification
access.redhat.com/security/cve/CVE-2026-6669
access.redhat.com/security/cve/CVE-2026-19888
security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_70698.json
bugzilla.redhat.com/show_bug.cgi?id=2539548
cve.org/CVERecord?id=CVE-2026-6668
nvd.nist.gov/vuln/detail/CVE-2026-6668
bugzilla.redhat.com/show_bug.cgi?id=2539546
cve.org/CVERecord?id=CVE-2026-6669
bugzilla.redhat.com/show_bug.cgi?id=2539545
cve.org/CVERecord?id=CVE-2026-19888
nvd.nist.gov/vuln/detail/CVE-2026-19888
ubuntu.com/security/CVE-2026-6669