CVE-2026-75874
Mozilla Firefox vulnerability
- Published18 Aug 2026
Description
Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:HAffected products
Remediation
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2039972
- https://www.mozilla.org/security/advisories/mfsa2026-74/
- https://www.mozilla.org/security/advisories/mfsa2026-78/
- https://www.mozilla.org/security/advisories/mfsa2026-83/
- https://www.mozilla.org/security/advisories/mfsa2026-84/
- https://www.mozilla.org/security/advisories/mfsa2026-85/
- https://www.mozilla.org/security/advisories/mfsa2026-87/
- https://www.mozilla.org/security/advisories/mfsa2026-88/
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-75874 being actively exploited?
CVE-2026-75874 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.46%.
How severe is CVE-2026-75874?
CVE-2026-75874 has a CVSS 3.1 base score of 10.0, rated critical. EPSS estimates a 0.46% probability of exploitation.
Which products are affected by CVE-2026-75874?
Affected products include Mozilla Firefox, Mozilla Thunderbird.
How do I fix CVE-2026-75874?
Upgrade affected software to a fixed version, for example Mozilla Firefox 154.0.0, Mozilla Thunderbird 154.0 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-75874 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.