Same-Origin Policy Bypass in Firefox and Firefox ESR
CVE-2025-13019

8.1HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
11 November 2025

What is CVE-2025-13019?

A vulnerability in the Workers component of the Firefox browser allows for a bypass of the same-origin policy, which could potentially allow malicious scripts to interact with content from different origins. Affected users running versions of Firefox below 145 and Firefox ESR below 140.5 may be at risk. It’s crucial for users to update their browsers to the latest versions to mitigate potential exploitation.

Affected Version(s)

Firefox < 145

Firefox ESR < 140.5

Thunderbird < 145

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1988412
https://www.mozilla.org/security/advisories/mfsa2025-87/
https://www.mozilla.org/security/advisories/mfsa2025-88/

CVSS V3.1

Score:
8.1
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Oskar L
JSON
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CVE-2025-13019 : Same-Origin Policy Bypass in Firefox and Firefox ESR