CVE-2020-12403: nss: CHACHA20-POLY1305 decryption with undersized tag leads to out-of-bounds read

Severity: Critical

CVSS Score: 9.1

A flaw was found in the way CHACHA20-POLY1305 was implemented in NSS in versions before 3.55. When using multi-part Chacha20, it could cause out-of-bounds reads. This issue was fixed by explicitly disabling multi-part ChaCha20 (which was not functioning correctly) and strictly enforcing tag length. The highest threat from this vulnerability is to confidentiality and system availability.