An integer overflow was discovered in the Layout: Text and Fonts rendering component. The flaw can corrupt memory while processing fonts or text layout and, if exploitable, could lead to arbitrary code execution or compromise of system integrity. The vulnerability is caused by an unchecked integer calculation that goes beyond the bounds of a data buffer, which is a classic form of integer overflow.

Mozilla Firefox web browsers are affected. The issue was addressed in Firefox release 158 and Firefox ESR 153.5. All earlier Firefox builds that have not applied these updates are vulnerable.

The EPSS score is not available and the vulnerability is not listed in the CISA KEV catalog, so the current exploitation probability is unknown. The advisory does not specify an explicit attack vector, but integer overflows in rendering paths can often be triggered by crafted web pages or local files. Based on the advisory, the risk is considered significant enough to warrant immediate remediation through an upgrade. No additional mitigations were documented by the CNA.