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CVE-2026-6668

Integer overflow causes an infinite loop in packet buffer growth in PgBouncer

7.5 HighFix available

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.57%Up 0.2 points since Sep 24, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

Integer overflow causes an infinite loop in packet buffer growth in PgBouncer

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
CVE-2026-6668
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-835
Updated
2026-11-02
EUVDEUVD-2026-85363 7.5

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
EUVD-2026-85363
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-r96c-7w9v-wrc8 7.5

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an...

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
GHSA-r96c-7w9v-wrc8
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190
Updated
2026-11-02
NVD 7.5

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
CVE-2026-6668
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-835
Updated
2026-11-02
OSVDEBIAN-CVE-2026-6668 7.5

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
DEBIAN-CVE-2026-6668
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/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 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-6668 7.5

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
UBUNTU-CVE-2026-6668
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVAZL-103433 No score

CVE-2026-6668 affecting package pgbouncer for versions less than 1.26.0-1

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
AZL-103433
Updated
2026-11-02
OSVBIT-pgbouncer-2026-6668 No score

Integer overflow causes an infinite loop in packet buffer growth in PgBouncer

Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.

Record
BIT-pgbouncer-2026-6668
Updated
2026-11-02

Affected packages

Affected packages
PackageAffectedFixed
pgbouncer
Azure Linux:3
before 1.26.0-1
1.26.0-1
pgbouncer
Bitnami
before 1.26.0
1.26.0
pgbouncer
Debian: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 less
1.20.1-11.21.0-11.22.0-11.22.1-11.23.0-11.23.1-11.24.0-21.24.0-31.24.1-11.25.0-11.25.0-21.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-6
None known
pgbouncer
Debian: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 less
1.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-6
None known
pgbouncer
Debian: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
pgbouncer
Red Hat:hummingbird:1
From an advisory covering 3 CVEs
before 0:1.26.0-0.1.hum1
0:1.26.0-0.1.hum1
pgbouncer
Ubuntu:16.04:LTS
All versions, plus listed versions
1.5.5-11.6.1-11.7-1
None known
pgbouncer
Ubuntu: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
pgbouncer
Ubuntu: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
pgbouncer
Ubuntu:22.04:LTS
All versions, plus listed versions
1.15.0-11.16.1-1ubuntu1
None known
pgbouncer
Ubuntu: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
pgbouncer
Ubuntu:26.10
All versions, plus listed versions
1.25.1-11.25.2-11.25.2-1ubuntu1
None known
pgbouncer
Ubuntu:26.04:LTS
All versions, plus listed versions
1.24.1-11.25.0-21.25.1-1
None known

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-6668 is a high vulnerability (CVSS 7.5) in pgbouncer, published September 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.57%, the 47th percentile. Fixed in pgbouncer 1.26.0-1.

References

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