Use‑after‑free vulnerabilities in the DOM core and HTML component of Firefox can corrupt memory. An attacker who can trigger a freed memory area to be accessed may cause the browser to crash, or if that memory is reallocated to attacker‑controlled content, arbitrary code execution may be achieved, compromising confidentiality, integrity, and potentially availability of the system.

Mozilla Firefox browsers are affected. All releases before version 159, and all ESR builds before 115.44 (ESR 115) or before 153.6 (ESR 153), contain the flaw and have been patched in the stated versions.

Based on the description, it is inferred that the likely attack vector is a maliciously crafted web page delivered to a user, which triggers the use‑after‑free condition. The use‑after‑free condition is a serious memory corruption flaw that typically permits remote code execution. No EPSS score is published, and the vulnerability is not listed in CISA's KEV catalog, but the high severity nature of use‑after‑free means exploitation likelihood remains significant in environments that serve malicious content.