Mozilla Network Security Services (NSS) before 3.21.4, 3.22.x through 3.28.x before 3.28.4, 3.29.x before 3.29.5, and 3.30.x before 3.30.1 allows remote attackers to cause a denial of service (out-of-bounds write) or possibly have unspecified other impact by leveraging incorrect base64 operations.