JavaScript Property Modification Issue in Mozilla Firefox and Thunderbird
CVE-2025-11711

6.5MEDIUM

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
14 October 2025

What is CVE-2025-11711?

A vulnerability exists in Mozilla's Firefox and Thunderbird that enables attackers to alter the values of JavaScript Object properties that should remain non-writable. This defect may lead to unexpected behavior in applications relying on predictable property states, potentially leading to further security issues.

Affected Version(s)

Firefox < 144

Firefox ESR < 115.29

Firefox ESR < 140.4

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1989978
https://www.mozilla.org/security/advisories/mfsa2025-81/
https://www.mozilla.org/security/advisories/mfsa2025-82/

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

EntryHi
JSON
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CVE-2025-11711 : JavaScript Property Modification Issue in Mozilla Firefox and Thunderbird