CVE-2025-4089: Potential local code execution in "copy as cURL" command

Severity: medium (CVSS 5.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-29 · updated 2026-09-30
Weakness: CWE-77

Description

Due to insufficient escaping of special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

Affected products

Mozilla Firefox: before 138.0 — fixed in 138.0
Mozilla Thunderbird: before 138.0 — fixed in 138.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 138.0; Mozilla Thunderbird 138.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1949994%2C1956698%2C1960198
https://www.mozilla.org/security/advisories/mfsa2025-28/
https://www.mozilla.org/security/advisories/mfsa2025-31/

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