Integer overflow in Pgbouncer
CVE-2026-6668
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.
Vulnerability class: Integer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.002
Affected products
- Pgbouncer
Weakness classification (CWE)
References
Frequently asked questions
- What is CVE-2026-6668?
- CVE-2026-6668 is a high-severity vulnerability in Pgbouncer, classified under Integer Overflow or Wraparound. CVSS score: 7.5/10. Published 2026-09-23.
- How severe is CVE-2026-6668?
- High severity. CVSS v3 base score is 7.5 out of 10.