What is CVE-2026-12293?

CVE-2026-12293 is a critical-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 9.8/10. Published 2026-06-16.

How severe is CVE-2026-12293?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Use After Free in Mozilla Firefox

CVE-2026-12293

Use-after-free in the Graphics: WebGPU component. This vulnerability was fixed in Firefox 152 and Thunderbird 152.

Vulnerability class: Use-After-Free

Published 2026-06-16 · last modified 2026-07-15.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.003 (20.6th percentile), scored 2026-09-30.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 21st percentile — 20.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Mozilla Firefox — versions 152
Mozilla Thunderbird — versions 152

Weakness classification (CWE)

References

bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
www.mozilla.org/security/advisories/mfsa2026-57/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2026-60/ (Vendor Advisory)
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Frequently asked questions

What is CVE-2026-12293?: CVE-2026-12293 is a critical-severity vulnerability in Mozilla Firefox, classified under Use After Free. CVSS score: 9.8/10. Published 2026-06-16.
How severe is CVE-2026-12293?: Critical severity. CVSS v3 base score is 9.8 out of 10.