# CVE-2026-6668: PgBouncer integer overflow in packet buffer growth

Source: https://junglewise.ai/threats/cve-2026-6668-integer-overflow-in-the-packet-buffer-growth-logic-in-pgbouncer  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-23. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-6668 · Severity: high · CVSS 7.5 · Published 2026-09-23

PgBouncer is a connection pooling middleware that manages client connections to PostgreSQL databases. An integer overflow in the packet buffer growth logic allows unauthenticated remote attackers to send specially crafted packets that trigger an infinite loop, consuming CPU and halting all database connections. Because the connection pool runs in a single process, the attack renders the pooling service unavailable until manually restarted.

Technologies: [PgBouncer](https://junglewise.ai/threats/technologies/pgbouncer-pgbouncer). Vendors: [PgBouncer](https://junglewise.ai/threats/vendors/pgbouncer).

## Quick answers

**Is CVE-2026-6668 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-6668 being exploited in the wild.

**How severe is CVE-2026-6668?** High severity, with a CVSS score of 7.5, published 23 September 2026.

**Which products and versions are affected?** PgBouncer through 1.25.2.

**Is there a fix for CVE-2026-6668?** A patch was published on 2026-09-23: Fixed in version 1.26.0 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-6668 attacked?** It is in a hosted service.

**Am I affected by CVE-2026-6668?** Check whether you run PgBouncer at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

An integer overflow in the packet buffer size computation allows an infinite growth loop when sufficiently large input is sent to the buffer. Both unauthenticated and authenticated code paths can reach the vulnerable logic. The attack is possible without authentication when max_packet_size is at its default value, causing the single-threaded PgBouncer process to saturate a CPU core and stall all pooled connections.

## Affected products

- PgBouncer PgBouncer through 1.25.2

## Timeline

- 2026-09-23: disclosed
- 2026-09-23: patched: Fixed in version 1.26.0

## References

- [https://www.pgbouncer.org/changelog.html](https://www.pgbouncer.org/changelog.html)

## Related threats

- [PgBouncer authentication bypass in SCRAM](https://junglewise.ai/threats/cve-2026-107350-improper-authentication-in-pgbouncer-1-17-0-through-1-26-0)
- [PgBouncer infinite loop denial of service in startup message parsing](https://junglewise.ai/threats/cve-2026-107349-an-infinite-loop-in-pgbouncer-1-20-0-through-1-26-0-allows-an)
- [PgBouncer uncontrolled CPU consumption in SCRAM authentication](https://junglewise.ai/threats/cve-2026-6669-missing-upper-bound-on-the-key-derivation-iteration-count-accepted)
- [Untrusted search path in auth_query connection handler in PgBouncer before 1.25.1 allows an unauthenticated attacker…](https://junglewise.ai/threats/cve-2025-12819-untrusted-search-path-in-auth-query-connection-handler-in)