CVE-2020-12387

Una condición de carrera cuando se ejecuta el código shutdown para Web Worker conllevo a una vulnerabilidad de uso de la memoria previamente liberada. Esto resultó en un bloqueo potencialmente explotable. Esta vulnerabilidad afecta a Firefox ESR versiones anteriores a 68.8, Firefox versiones anteriores a 76 y Thunderbird versiones anteriores a 68.8.0.

A flaw was found in Mozilla Firefox and Thunderbird. When running shutdown code for Web Worker, a race condition occurs leading to a use-after-free memory flaw that could lead to an exploitable crash. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

Multiple security issues were discovered in Thunderbird. If a user were tricked in to opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, or execute arbitrary code. It was discovered that Thunderbird did not correctly handle Unicode whitespace characters within the From email header. An attacker could potentially exploit this to spoof the sender email address that Thunderbird displays.