CVE-2026-2790highCWE-346

CVE-2026-2790: high-severity vulnerability in Mozilla Firefox

Same-origin policy bypass in the Networking: JAR component

Published 24 Feb 2026 · Updated 13 Apr 2026

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21Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 8.8epss 0.3%

Same-origin policy bypass in the Networking: JAR component. This vulnerability was fixed in Firefox 148, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.

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

Affected products

Mozilla · Firefox Mozilla · Thunderbird

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In the same product, most dangerous first.

CVE-2016-9079HIGHCVE-2016-9079EPSS 87.4%KEV CVE-2019-11708CRITICALCVE-2019-11708EPSS 55.9%KEV CVE-2019-17026HIGHCVE-2019-17026EPSS 46.3%KEV CVE-2019-11707HIGHCVE-2019-11707EPSS 38.0%KEV CVE-2024-9680CRITICALCVE-2024-9680EPSS 23.2%KEV CVE-2022-26485HIGHCVE-2022-26485EPSS 14.3%KEV

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2008426 https://www.mozilla.org/security/advisories/mfsa2026-13/https://www.mozilla.org/security/advisories/mfsa2026-15/https://www.mozilla.org/security/advisories/mfsa2026-16/https://www.mozilla.org/security/advisories/mfsa2026-17/