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.
Published: 2026-10-14
Score: 5.9 Medium
EPSS: n/a
KEV: No
AI Analysis

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Remediation

Vendor Workaround

Set max_packet_size to 2147483647 (the default) or lower.

Tracking

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Advisories

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References
Link Providers
https://www.pgbouncer.org/changelog.html cve-icon cve-icon
History

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'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: PostgreSQL

Published:

Updated: 2026-10-14T17:34:29.838Z

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

Link: CVE-2026-107348

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

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

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

Link: CVE-2026-107348

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-14T21:15:07Z

Weaknesses
  • CWE-190

    Integer Overflow or Wraparound

  • CWE-835

    Loop with Unreachable Exit Condition ('Infinite Loop')