A numeric injection point exists in the Auth Endpoint of kortix‑ai Suna where the router.replace or router.push functions accept a returnURL parameter without proper sanitization, enabling an attacker to inject arbitrary script payloads. This flaw aligns with CWE‑79 (Cross‑Site Scripting) and CWE‑94 (Improper Control of Generation of Code) and can be used to deface pages, steal session cookies, or perform other client‑side attacks. The vulnerability is reachable remotely and the exploit code is publicly disclosed, giving attackers a ready‑to‑use means to compromise affected users.

The flaw affects kortix‑ai Suna versions up to and including 0.8.38. The product is available in the open source repository at https://github.com/kortix‑ai/suna/. Users should update to version 0.8.39 (commit f5dec7aa) or newer to eliminate the flaw.

The CVSS base score of 5.3 indicates moderate severity, and no EPSS data is available, though the exploit is publicly accessible. The vulnerability is not listed in CISA KEV, but its remote nature and public exploit raise concern. Attackers can craft a malicious URL with a manipulated returnURL, trigger the redirect and deliver the payload entirely from client side.