CVE-2021-29984

Una reordenación de instrucciones resultaba en una secuencia de instrucciones que causaría que un objeto fuera considerado incorrectamente durante la recogida de basura. Esto conllevaba a una corrupción de la memoria y un bloqueo potencialmente explotable. Esta vulnerabilidad afecta a Thunderbird versiones anteriores a 78.13, Thunderbird versiones anteriores a 91, Firefox ESR versiones anteriores a 78.13, y Firefox versiones anteriores a 91.

It was discovered that Thunderbird didn't ignore IMAP server responses prior to completion of the STARTTLS handshake. A person-in-the-middle could potentially exploit this to trick Thunderbird into showing incorrect information. 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, or execute arbitrary code. Various other issues were also addressed.