CVE-2020-15667: Mozilla Firefox

High severity, CVSS 8.8. EPSS: 1.6% chance of exploitation in the next 30 days.

When processing a MAR update file, after the signature has been validated, an invalid name length could result in a heap overflow, leading to memory corruption and potentially arbitrary code execution. Within Firefox as released by Mozilla, this issue is only exploitable with the Mozilla-controlled signing key. This vulnerability affects Firefox < 80.

Affected products

• Mozilla Firefox: before 80.0 (fixed in 80.0)

Published 2020-10-01. Last modified 2026-06-17.