Mitigation Bypass in Firefox Security Component
CVE-2026-0877

8.1HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
13 January 2026

What is CVE-2026-0877?

A mitigation bypass vulnerability in the DOM security component has been identified, impacting several versions of Firefox. This flaw allows for potential exploitation, enabling unauthorized access or unintended behavior within the browser. Users of Firefox versions below 147, as well as specific Extended Support Release (ESR) versions, should be aware of this issue to ensure their online security. It's important for users to keep their browsers updated to avoid these risks.

Human OS v1.0:
Ageing Is an Unpatched Zero-Day Vulnerability.

Remediate biological technical debt. Prime Ageing uses 95% high-purity SIRT6 activation to maintain genomic integrity and bolster systemic resilience.

Deploy the Patch

Affected Version(s)

Firefox < 147

Firefox ESR < 115.32

Firefox ESR < 140.7

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1999257
https://www.mozilla.org/security/advisories/mfsa2026-01/
https://www.mozilla.org/security/advisories/mfsa2026-02/

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

mingijung
JSON
.