RCE in Mozilla Firefox
CVE-2025-5265
Due to insufficient escaping of the ampersand character 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 139, Firefox ESR 115.24, Firefox ESR 128.11, Thunderbird 139, and Thunderbird 128.11.
Vulnerability class: Command Injection (OS Command Injection)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.002 (10.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: +0.000
Affected products
- Mozilla Firefox — versions 115.24, 128.11, 139
- Mozilla Thunderbird — versions 128.11, 139
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2025-42/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-43/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-44/ (Vendor Advisory)
- www.mozilla.org/security/advisories/mfsa2025-45/
- www.mozilla.org/security/advisories/mfsa2025-46/
Frequently asked questions
- What is CVE-2025-5265?
- CVE-2025-5265 is a medium-severity vulnerability in Mozilla Firefox, classified under Command Injection. CVSS score: 4.8/10. Published 2025-05-27.
- How severe is CVE-2025-5265?
- Medium severity. CVSS v3 base score is 4.8 out of 10.