CVE-2025-4089
MediumCVSS 5.1Exploitation Probability (EPSS)
Low risk7th percentile - higher than 7% of all known CVEs
Summary
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.
Risk Assessment
An attacker could achieve remote code execution on the victim's machine, potentially leading to full system compromise.
Recommendation
Update Firefox or Thunderbird to version 138 or later.
Other vulnerabilities in Firefox
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Incorrect boundary conditions in the Layout: Block and Inline component. This vulnerability was fixed in Firefox 159.0.1.
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Mozilla blocked compromised intermediate eMudhra certificates via OneCRL on October 17, and the list was distributed to clients via RemoteSettings the same day. This update contains the updated OneCRL block list, ensuring clients will block the compromised certificates even if RemoteSettings is disabled by policy or otherwise unavailable in the user's network environment. The vulnerability was fixed in Firefox 158.0.1, Firefox ESR 153.5.1, Firefox ESR 115.43.1, Thunderbird 158.0.1, and Thunderbird 153.5.1.
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A denial-of-service vulnerability exists in the PDF Viewer component. The vulnerability was fixed in Firefox 158.0.1 and Thunderbird 158.0.1.
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Vulnerability in the DOM: Core & HTML component allows mitigation bypass. This issue was fixed in Firefox 158 and Thunderbird 158.
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Invalid pointer and undefined behavior in the DOM: Notifications component. Fixed in Firefox 158 and Thunderbird 158.
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Same-origin policy bypass in the DevTools component. Fixed in Firefox 158 and Thunderbird 158.
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A vulnerability in the DOM: Content Processes component allows sandbox escape. It was fixed in Firefox 158 and Thunderbird 158.
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A vulnerability in the DOM: Web Authentication component causes a site isolation issue. It was fixed in Firefox 158 and Thunderbird 158.
- CVE-2026-109745Critical
Sandbox escape due to uninitialized memory in the DOM: Web Serial component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109740Critical
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. The flaw was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS