CVE-2026-8958

Information disclosure, sandbox escape in the Security: Process Sandboxing component

CVSS 8.6 HIGHEPSS 0.3%CWE-668 CWE-693

Vexday Risk Score

21Low

SSVC decision (CISA)

Track

No exploitation signal → monitor

CVSS 8.6EPSS 0.3%KEV nãoPoC —Nuclei —Metasploit —Patch —

Lifecycle

19 May 2026Published on NVD

Recommendation: Monitor — no exploitation signal at the moment.

Information disclosure, sandbox escape in the Security: Process Sandboxing component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

Affected products

Mozilla · Firefox Mozilla · Thunderbird

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References

https://bugzilla.mozilla.org/show_bug.cgi?id=2034713 https://www.mozilla.org/security/advisories/mfsa2026-46/https://www.mozilla.org/security/advisories/mfsa2026-48/https://www.mozilla.org/security/advisories/mfsa2026-50/https://www.mozilla.org/security/advisories/mfsa2026-51/