CVE-2026-4690
High
Description
Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
SeverityHigh
CVSS8.6
Exploit probability—
Product
Mozilla Firefox
PublishedMar 24, 2026
First seenMar 24, 2026
Weakness typeCWE-190Integer overflowCWE-120CWE-120
How to fix
Update
- mozilla firefox115.34.0, 149.0, 140.9.0 or later
Vendor advisories
- access.redhat.com/errata/RHSA-2026:8427
- access.redhat.com/errata/RHSA-2026:7843
- access.redhat.com/errata/RHSA-2026:8315
- access.redhat.com/errata/RHSA-2026:5931
- access.redhat.com/errata/RHSA-2026:6342
- access.redhat.com/errata/RHSA-2026:5932
- access.redhat.com/errata/RHSA-2026:6917
- access.redhat.com/errata/RHSA-2026:7840
- access.redhat.com/errata/RHSA-2026:8285
- access.redhat.com/errata/RHSA-2026:7858
- access.redhat.com/errata/RHSA-2026:8850
- access.redhat.com/errata/RHSA-2026:7842
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 115.34.0, v < 149.0, 128.0 ≤ v < 140.9.0 | 115.34.0, 149.0, 140.9.0 |
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