High severity · published Oct 14, 2026
CVE-2026-107350
Authentication bypass via second StartupMessage during SCRAM authentication in PgBouncer
8.8
CVSS
0.4%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 31% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
PG
PgBouncer ·
1.17.0 before 1.26.1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-107350
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-107350
www.pgbouncer.org
https://www.pgbouncer.org/changelog.html
More from PgBouncer
9.8
CVE-2026-6665
PgBouncer buffer overflow in SCRAM
8.1
CVE-2025-12819
Untrusted search path in auth_query connection in PgBouncer
7.5
CVE-2026-107349
Infinite loop on empty option name in startup options parameter in PgBouncer
7.5
CVE-2026-19888
NULL pointer dereference in SCRAM client-final-message parsing in PgBouncer
7.5
CVE-2026-6668
Integer overflow causes an infinite loop in packet buffer growth in PgBouncer