CVE-2024-6603: Mozilla Firefox

High severity, CVSS 7.4. EPSS: 0.5% chance of exploitation in the next 30 days.

In an out-of-memory scenario an allocation could fail but free would have been called on the pointer afterwards leading to memory corruption. This vulnerability affects Firefox < 128, Firefox ESR < 115.13, Thunderbird < 115.13, and Thunderbird < 128.

Affected products

• Mozilla Firefox: before 115.13 (fixed in 115.13); before 128.0 (fixed in 128.0)
• Mozilla Thunderbird: before 115.13 (fixed in 115.13); from 116.0, before 128.0 (fixed in 128.0)

Published 2024-07-09. Last modified 2026-06-17.