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.
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

Set max_packet_size to 2147483647 (the default) or lower.

History

Sat, 17 Oct 2026 06:45:00 +0000

Type Values Removed Values Added
First Time appeared Pgbouncer
Pgbouncer pgbouncer
Vendors & Products Pgbouncer
Pgbouncer pgbouncer

Fri, 16 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 15 Oct 2026 13:30:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Moderate


Wed, 14 Oct 2026 17:45:00 +0000

Type Values Removed Values Added
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.
Title Integer overflow causes an infinite loop in message buffer growth in PgBouncer
Weaknesses CWE-190
CWE-835
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: PostgreSQL

Published:

Updated: 2026-10-16T20:11:22.132Z

Reserved: 2026-10-07T19:13:32.963Z

Link: CVE-2026-107348

cve-icon Vulnrichment

Updated: 2026-10-16T20:11:17.008Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-10-14T18:17:25.430

Modified: 2026-10-16T21:17:18.243

Link: CVE-2026-107348

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-14T17:34:29Z

Links: CVE-2026-107348 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-17T06:30:05Z

Weaknesses