MuJS, the lightweight JavaScript engine embedded in Ghostscript, contains a flaw in jsR_isindex() where a numeric array index that exceeds floating‑point limits is silently converted to an integer without range checks. This erroneous conversion triggers undefined behavior and can terminate the process. The immediate consequence is a denial of service, as the offending JavaScript payload can halt the host application that relies on MuJS.

Any deployment that uses the MuJS engine, particularly the Ghostscript distribution that incorporates the e892c9fdb revision, is potentially impacted. The vulnerability is tied to the specific commit referenced in the Bugzilla and Git commits linked in the advisory. Because no vendor or product version list is publicly provided, it is advisable to treat all earlier Ghostscript builds that include MuJS as vulnerable until a patched build is released.

The CVSS score of 7.5 and an EPSS score of < 1% indicate a moderate‑to‑high severity though exploitation probability is very low. It is not listed in the CISA KEV catalog. The factor that remains is that the flaw can be triggered by supplying crafted JavaScript to any component that invokes MuJS, such as rendering PDF files or processing online scripts. Without an official patch or workaround, the most realistic risk involves an attacker controlling the JavaScript input environment, for example by embedding malicious scripts in PDF documents. Once triggered, the process abort leads to a denial of service, but no direct information disclosure or code execution is reported.