CVE-2026-6748
Critical
Description
Uninitialized memory in the Audio/Video: Web Codecs component. This vulnerability was fixed in Firefox 150, Firefox ESR 140.10, Thunderbird 150, and Thunderbird 140.10.
SeverityCritical
CVSS9.8
Exploit probability34. percentile0.4%
Product
Mozilla Firefox
PublishedApr 21, 2026
First seenApr 21, 2026
Weakness typeCWE-457CWE-457CWE-824CWE-824
How to fix
Update
- mozilla firefox140.10.0, 150.0 or later
- mozilla thunderbird140.10.0 or later
Vendor advisories
- access.redhat.com/errata/RHSA-2026:19704
- access.redhat.com/errata/RHSA-2026:17690
- access.redhat.com/errata/RHSA-2026:19463
- access.redhat.com/errata/RHSA-2026:10767
- access.redhat.com/errata/RHSA-2026:12285
- access.redhat.com/errata/RHSA-2026:19041
- access.redhat.com/errata/RHSA-2026:19131
- access.redhat.com/errata/RHSA-2026:10766
- access.redhat.com/errata/RHSA-2026:13537
- access.redhat.com/errata/RHSA-2026:19655
- access.redhat.com/errata/RHSA-2026:19465
- access.redhat.com/errata/RHSA-2026:19542
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 140.10.0, v < 150.0 | 140.10.0, 150.0 |
| mozilla thunderbird | v < 140.10.0 | 140.10.0 |
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