CVE-2026-43964 Details

A buffer over-read vulnerability has been identified in Postfix versions prior to 3.8.16, 3.9 prior to 3.9.10, and 3.10 prior to 3.10.9. This vulnerability can cause a process crash by allowing an enhanced status code to be interpreted incorrectly when it lacks accompanying text after the third number. The issue arises in the proxymap daemon, which can dereference an uninitialized pointer after a request protocol error, leading to process termination. While this specific defect is not exposed to users, the buffer over-read can be triggered under certain conditions, such as with an access table response, a policy server response, or through pipe-to-command output, among other scenarios.

Users can upgrade to Postfix 3.11.2 or Postfix 3.10.9 to address this vulnerability.