CVE-2025-4084: firefox Improper Encoding — Fix

Description

Due to insufficient escaping of the 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 bug only affects Firefox for Windows. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox ESR 128.10, Firefox ESR 115.23, and Thunderbird 128.10.

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CVSS v3.1 Score

5.7

MEDIUM

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

Weakness Type (CWE)

CWE-116 CWE-116

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 115.23
mozilla	firefox	128.0 — 128.10
mozilla	thunderbird	< 128.10.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-29/ https://www.mozilla.org/security/advisories/mfsa2025-30/ https://www.mozilla.org/security/advisories/mfsa2025-32/

Other References

https://bugzilla.mozilla.org/buglist.cgi?bug_id=1949994%2C1956698%2C1960198 https://lists.debian.org/debian-lts-announce/2025/05/msg00022.html

Frequently Asked Questions

What is CVE-2025-4084? +

Due to insufficient escaping of the 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 bug only affects Firefox for Windows. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox ESR 128.10, Firefox ESR 115.23, and Thunderbird 128.10. It has a CVSS v3.1 base score of 5.7 (MEDIUM).

How severe is CVE-2025-4084? +

CVE-2025-4084 has a CVSS v3.1 score of 5.7 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-4084? +

CVE-2025-4084 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-4084? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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