The vulnerability is a missing authentication guard on two pgAdmin 4 SQL editor endpoints, allowing an attacker to reach a pickle deserialization sink without being logged in. Because the deserialization occurs on data stored in the session, the attacker needs a pre‑crafted session file with a malicious pickle payload and also must know the pgAdmin Flask SECRET_KEY and have write permission to the sessions/ directory on the host. When those preconditions are met, the flaw permits arbitrary code execution in the pgAdmin process and, consequently, on the underlying host system. This weakness is classified as a missing‑auth‑on‑critical‑function with insecure deserialization (CWE‑306, CWE‑502).

Affected systems are pgAdmin 4 deployments running in server mode with versions 6.9 through 9.15 inclusive. The vulnerability does not affect Desktop mode, where authentication is enforced on every request.

Risk assessment: The CVSS score is 9.5, indicating critical severity, and the flaw is not listed in the CISA KEV catalog. The EPSS score is unavailable, but because the weakness requires additional preconditions—SECRET_KEY exposure and write access to the sessions directory—exploitation likelihood remains limited to scenarios where the attacker already has those capabilities or the system is misconfigured. Nevertheless, once those conditions exist, the missing authentication gate turns a partial compromise into full remote code execution.