CVE-2025-6425 - CVE House
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Status published Unknown CVE-2025-6425

The WebCompat WebExtension shipped with Firefox exposed a persistent UUID

Vulnerability Description

An attacker who enumerated resources from the WebCompat extension could have obtained a persistent UUID that identified the browser, and persisted between containers and normal/private browsing mode, but not profiles. This vulnerability was fixed in Firefox 140, Firefox ESR 115.25, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • Rob Wu

References

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Affected Vendor

Affected Software

Firefox, Thunderbird
Vulnerable Versions:
115.25, 128.12, 140

Timeline

Official Publish: June 24th, 2025
Last Modified: April 13th, 2026
Added to House: July 22nd, 2026

CVSS Vectors

No vector data available

Weaknesses (CWE)

No CWE data available

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.