CVE-2020-26973

Determinadas entradas hacia el CSS Sanitizer lo confundieron, resultando en una eliminación de componentes incorrectos. Esto podría haber sido usado como una omisión de saneo. Esta vulnerabilidad afecta a Firefox versiones anteriores a 84, Thunderbird versiones anteriores a 78,6 y Firefox ESR versiones anteriores a 78,6

The Mozilla Foundation Security Advisory describes this flaw as: Certain input to the CSS Sanitizer confused it, resulting in incorrect components being removed. This could have been used as a sanitizer bypass.

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, obtain sensitive information, bypass the CSS sanitizer, or execute arbitrary code. It was discovered that the proxy.onRequest API did not catch view-source URLs. If a user were tricked in to installing an extension with the proxy permission and opening View Source, an attacker could potentially exploit this to obtain sensitive information. Various other issues were also addressed.