CVE-2021-23954

Usando los nuevos operadores de asignación lógica en una declaración de cambio de JavaScript podría haber causado una confusión de tipos, conllevando a una corrupción de la memoria y un bloqueo potencialmente explotable. Esta vulnerabilidad afecta a Firefox versiones anteriores a 85, Thunderbird versiones anteriores a 78,7 y Firefox ESR versiones anteriores a 78,7

The Mozilla Foundation Security Advisory describes this flaw as: Using the new logical assignment operators in a JavaScript switch statement could have caused a type confusion, leading to a memory corruption and a potentially exploitable crash.

Multiple security issues were discovered in Thunderbird. If a user were tricked into opening a specially crafted website in a browsing context, an attacker could potentially exploit these to cause a denial of service, obtain sensitive information, or execute arbitrary code. It was discovered that responses received during the plaintext phase of the STARTTLS connection setup were subsequently evaluated during the encrypted session. A person in the middle could potentially exploit this to perform a response injection attack. Various other issues were also addressed.