What’s Vulnerable › Vulnerabilities
CVE-2026-107350: Authentication bypass via second StartupMessage during SCRAM authentication in PgBouncer
- Severity: high (CVSS 8.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.4% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-14 · updated 2026-10-16
- Weakness: CWE-287
Description
Improper authentication in PgBouncer 1.17.0 through 1.26.0 allows a remote attacker who knows the password of a user listed in auth_file to log in as any other user that authenticates using SCRAM, including PgBouncer admin users and backend superusers. A second StartupMessage sent during SCRAM authentication against a non-existent database is not rejected and switches the user being logged in as, while the SCRAM exchange is still verified against the keys of the first user.
Affected products
- PgBouncer: from 1.17.0 before 1.26.1 — fixed in 1.26.1
How to fix
Upgrade to a fixed version: PgBouncer 1.26.1. Check the vendor advisory for mitigations.
References
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