CVE-2026-8949

What it is

Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.6% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-19 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-14 20:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-19 14:16 UTC

Last modified

2026-10-14 20:10 UTC

Exploit probability

0.6% · EPSS, next 30 days

Weakness

CWE-190 · Integer overflow

Record status

Analyzed

Affected

• Mozilla Firefox < 140.11.0
• Mozilla Firefox < 151.0.0
• Mozilla Thunderbird < 140.11
• Mozilla Thunderbird < 151.0.0

Attack profile CVSS 3.1 · 7.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High