PgBouncer Stack Overflow Vulnerability in SCRAM Authentication Handling

A stack overflow vulnerability has been identified in PgBouncer versions prior to 1.25.2, specifically within the SCRAM authentication process. The issue arises because the SCRAM code did not properly validate the return value of the strlcat() function when constructing the SCRAM client-final-message. This flaw can be exploited by a malicious backend that sends a SCRAM server-final-message containing a lengthy nonce.

Impact

Exploitation of this vulnerability leads to a stack overflow, which can potentially be exploited to execute arbitrary code or cause a denial-of-service condition by crashing the application.

Remediation

Users can upgrade to PgBouncer version 1.25.2 or later to address this vulnerability.