A flaw in pgAdmin 4 causes the client library libpq to fall back to the operating‑system account’s Kerberos credential cache when Kerberos authentication is not intended. As a result, any user can establish a PostgreSQL connection that presents the service account’s Kerberos principal, bypassing the intended user name. This leads to unauthorized authentication and the ability to act with higher privileges. The weakness is a form of privilege escalation (CWE‑1188) and can expose credential information (CWE‑522).

The vulnerability exists in pgAdmin 4 versions prior to 9.19. It affects installations on both Windows and Unix‑like systems where pgAdmin runs under a service account that may possess Kerberos credentials. The issue also applies when utilities such as psql are invoked from pgAdmin’s environment.

The CVSS base score is 7.1, indicating a high severity. The EPSS score is not available, so the current probability of exploitation is unknown, and the vulnerability is not listed in CISA’s KEV catalog. The attack can be carried out by a local user who can execute pgAdmin or its utilities; the attacker need only have permission to run the program on a host that possesses or can obtain the service account’s Kerberos cache. Once executed, the fallback mechanism delivers the cached ticket to any PostgreSQL server that requests GSSAPI authentication, allowing the attacker to authenticate as the privileged service account. Because the library is unaware of the intended authentication method, this bypass can occur even when gssencmode=disable is set, making the exploit reliable under the described conditions.