Privilege Escalation in Firefox Browser by Mozilla
CVE-2026-2780

8.8HIGH

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
24 February 2026

What is CVE-2026-2780?

A privilege escalation vulnerability exists in the Netmonitor component of the Mozilla Firefox browser. This flaw can allow an attacker to gain elevated privileges, posing a significant risk to user data and system integrity. It affects versions of Firefox prior to 148 and Firefox ESR versions prior to 140.8. Users are encouraged to update their browsers to recent versions to mitigate this risk and ensure their online security.

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Affected Version(s)

Firefox < 148

Firefox ESR < 140.8

Thunderbird < 148

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2007829
https://www.mozilla.org/security/advisories/mfsa2026-13/
https://www.mozilla.org/security/advisories/mfsa2026-15/

CVSS V3.1

Score:
8.8
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

RyotaK
JSON
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