Vulnerability · Published Sep 23, 2026 · Assigned by PostgreSQL
CVE-2026-6668Integer overflow causes an infinite loop in packet buffer growth in PgBouncer
High 7.5
In plain English
A high-severity integer overflow in PgBouncer. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | pgbouncer | no fix listed | DEBIAN-CVE-2026-6668 |
| Debian:13 | pgbouncer | no fix listed | DEBIAN-CVE-2026-6668 |
| Debian:14 | pgbouncer | 1.26.0-1 | DEBIAN-CVE-2026-6668 |
| Ubuntu:22.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6668 |
| Ubuntu:24.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6668 |
| Ubuntu:26.04:LTS | pgbouncer | no fix listed | UBUNTU-CVE-2026-6668 |
| Ubuntu:26.10 | pgbouncer | no fix listed | UBUNTU-CVE-2026-6668 |
Affected products (as reported)
Weakness: CWE-190, CWE-835 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H