Vulnerability Intelligence Report
Sandbox escape in the Remote Settings Client component
CVE-2026-75874
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.
No Active Exploit Signals
CVSS Base Score
10.0
CRITICAL
Exploitability:3.9
Impact Score:6.1
EPSS Probability:0.40%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
—
Authentication
—
Weaponization
—
SSVC Action
—
Weaknesses (CWE)
CWE-693 ↗CWE-693 Protection Mechanism Failure
Affected Products & Versions
| Vendor | Product | Affected Versions |
|---|---|---|
| Mozilla | Firefox | 115.40 <= 115.* (unaffected), 140.15 <= 140.* (unaffected), 153.2 <= 153.* (unaffected), 154 <= * (unaffected) |
| Mozilla | Thunderbird | 140.15 <= 140.* (unaffected), 153.2 <= 153.* (unaffected), 154 <= * (unaffected) |
References & Technical Advisories
No reference links found.
Threat Intelligence Signals
EPSS Score
0.403%
GitHub Advisory
Identity & Timeline
| Status | PUBLISHED |
| Assigning Authority | Mozilla Corporation · Vendor · USA |
| Reserved | 2026-08-18T12:23:35 |
| Published | 2026-08-18T12:23:35 |
| Last Updated | 2026-09-01T21:44:07 |
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