CVE-2025-0240

4.0 MEDIUM 0.7% exploit odds Fix listed Memory safety Browser & mail

What it is

Parsing a JavaScript module as JSON could, under some circumstances, cause cross-compartment access, which may result in a use-after-free. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. Limited direct impact.
Exploit odds: 0.7% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2025-01-07 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-05 15:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.7% in the next 30 days (EPSS).
Severity: 4.0 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2025-01-07 16:15 UTC
Last modified: 2026-10-05 15:10 UTC
Exploit probability: 0.7% · EPSS, next 30 days
Weakness: CWE-416 · Use after free
Record status: Modified

Affected

Mozilla Firefox < 128.6.0
Mozilla Firefox < 134.0
Mozilla Thunderbird < 128.6.0
Mozilla Thunderbird < 134.0

Attack profile CVSS 3.1 · 4.0

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: Low
Availability: None

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2025-0240.md and follow it. Check whether this project is affected by CVE-2025-0240. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record