CVE-2024-7520

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-08-06 · updated 2026-06-17
Weakness: CWE-843

Description

A type confusion bug in WebAssembly could be leveraged by an attacker to potentially achieve code execution. This vulnerability affects Firefox < 129, Firefox ESR < 128.1, and Thunderbird < 128.1.

Affected products

Mozilla Firefox: before 129.0 — fixed in 129.0
Mozilla Firefox ESR: before 128.1.0 — fixed in 128.1.0
Mozilla Thunderbird: before 128.1.0 — fixed in 128.1.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 129.0; Mozilla Firefox ESR 128.1.0; Mozilla Thunderbird 128.1.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1903041
https://www.mozilla.org/security/advisories/mfsa2024-33/
https://www.mozilla.org/security/advisories/mfsa2024-35/
https://www.mozilla.org/security/advisories/mfsa2024-37/

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