# CVE-2026-107348: Integer overflow causes an infinite loop in message buffer growth in PgBouncer

CVE-2026-107348 is fixed in pgbouncer on 1 platform by DEBIAN-CVE-2026-107348 (version 1.26.1-1), released October 16, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-107348
- Priority: Routine
- CVSS: 5.9 (Moderate)
- EPSS: 0.0039
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 14, 2026
- Weakness: Integer Overflow or Wraparound
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-107348

## Description

Integer overflow in the message buffer growth logic (mbuf_make_room) in PgBouncer 1.21.0 through 1.26.0 allows a remote attacker to cause a denial of service when max_packet_size is configured above 2147483648. A packet header declaring a length above 2^31 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 restarted. Since 1.23.0 the overflow is reachable before authentication with a five-byte packet header.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | pgbouncer Debian 14 | 1.26.1-1 | [DEBIAN-CVE-2026-107348](https://patchblox.com/security/data/fix/linux/debian-cve-2026-107348.md) | Oct 16, 2026 |

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Data as of 2026-11-09T01:18:40Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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