CVE-2026-107349: Loop with Unreachable Exit Condition ('Infinite Loop') in PgBouncer
Description
CVE-2026-107349 is a high-severity vulnerability in PgBouncer versions 1.20.0 through 1.26.0 that allows an unauthenticated remote attacker to cause a denial of service via an infinite loop. The issue arises when a StartupMessage contains an empty parameter name, causing a lookup loop that saturates a CPU core and makes PgBouncer unresponsive until restarted.
CVSS v3.1
Score 7.5high
Affected software
PgBouncer
pkg:github/pgbouncer/pgbouncerRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
PgBouncer versions 1.20.0 through 1.26.0 contain an infinite loop vulnerability triggered by a StartupMessage with an options parameter containing an empty parameter name (e.g., "-c="). This causes the ignore_startup_parameters list lookup to loop indefinitely. Since PgBouncer handles all clients in a single process, this infinite loop saturates a CPU core, resulting in denial of service by making PgBouncer unresponsive until the process is restarted.
Potential Impact
An unauthenticated remote attacker can exploit this vulnerability to cause a denial of service by saturating a CPU core with an infinite loop, rendering PgBouncer unresponsive to all clients until the process is restarted. There is no impact on confidentiality or integrity.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, consider implementing network-level protections to restrict access to PgBouncer or monitoring for anomalous StartupMessage traffic patterns that could trigger the infinite loop.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- PostgreSQL
- Date Reserved
- 2026-10-07T19:13:32.963Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6acfc0ee2cdf04f6569bc5c5
Added to database: 10/14/2026, 17:50:38 UTC
Last enriched: 10/14/2026, 18:03:39 UTC
Last updated: 10/14/2026, 19:00:31 UTC
Views: 8
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