CVE-2025-8027

CVE-2025-8027: JavaScript engine only wrote partial return value to stack

Published July 22, 2025
Last update April 13, 2026

CVSS base score

What the vulnerability does

Description

On 64-bit platforms IonMonkey-JIT only wrote 32 bits of the 64-bit return value space on the stack. Baseline-JIT, however, read the entire 64 bits. This vulnerability was fixed in Firefox 141, Firefox ESR 115.26, Firefox ESR 128.13, Firefox ESR 140.1, Thunderbird 141, Thunderbird 128.13, and Thunderbird 140.1.

Key dates

Disclosure timeline

July 22, 2025 CVE published
April 13, 2026 Record updated