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9.8
Firefox and Thunderbird Privilege Escalation Risk in Netmonitor Component
CVE-2026-2782
Summary
Older versions of Firefox and Thunderbird have a security issue where an attacker could potentially exploit a weakness in the Netmonitor component to gain elevated privileges. This could allow malicious code to take control of the system. Update to the latest version to fix this issue.
What to do
No fix is available yet. Check with your software vendor for updates.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| mozilla | firefox | <= 140.8.0 | – |
| mozilla | firefox | <= 148.0 | – |
| mozilla | thunderbird | <= 140.8.0 | – |
| mozilla | thunderbird | <= 148.0 | – |
Original title
Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
Original description
Privilege escalation in the Netmonitor component. This vulnerability affects Firefox < 148, Firefox ESR < 140.8, Thunderbird < 148, and Thunderbird < 140.8.
nvd CVSS3.1
9.8
Vulnerability type
CWE-269
Improper Privilege Management
- https://bugzilla.mozilla.org/show_bug.cgi?id=2010743 Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-13/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-15/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-16/ Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-17/ Vendor Advisory
Published: 24 Feb 2026 · Updated: 12 Mar 2026 · First seen: 6 Mar 2026