Critical (9.8). EPSS 10% chance of exploitation in the next 30 days.
Heap-based buffer overflow in the ASN.1 decoder in Mozilla Network Security Services (NSS) before 3.19.2.1 and 3.20.x before 3.20.1, as used in Firefox before 42.0 and Firefox ESR 38.x before 38.4 and other products, allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via crafted OCTET STRING data.
Severity
CVSS 3.0
9.8 critical
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
10% chance of exploitation in the next 30 days; higher than 95% of CVEs (scores of 2026-10-31)