VulnerabilityModified
CVE-2026-0878
This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
HIGH 8.0EPSS 0.48%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.48%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 147, Firefox ESR 140.7, Thunderbird 147, and Thunderbird 140.7.
- CVSS 3.1
- 8.0 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N
- EPSS
- 0.48% probability · 40th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-20, CWE-119
- Affected
- mozilla/firefox · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2003989Permissions Required
- https://www.mozilla.org/security/advisories/mfsa2026-01/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-03/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-04/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2026-05/Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:0667
- https://access.redhat.com/errata/RHSA-2026:0694
- https://access.redhat.com/errata/RHSA-2026:0924
- https://access.redhat.com/errata/RHSA-2026:1320
- https://access.redhat.com/errata/RHSA-2026:1413
- https://access.redhat.com/errata/RHSA-2026:1414
- https://access.redhat.com/errata/RHSA-2026:1415
- https://access.redhat.com/errata/RHSA-2026:1461
- https://access.redhat.com/errata/RHSA-2026:1462
- https://access.redhat.com/errata/RHSA-2026:1471
- https://access.redhat.com/errata/RHSA-2026:1487
- https://access.redhat.com/errata/RHSA-2026:2041
- https://access.redhat.com/errata/RHSA-2026:2043
- https://access.redhat.com/errata/RHSA-2026:2044
- https://access.redhat.com/errata/RHSA-2026:2047
- https://access.redhat.com/errata/RHSA-2026:2069
- https://access.redhat.com/errata/RHSA-2026:2070
- https://access.redhat.com/errata/RHSA-2026:2073
- https://access.redhat.com/errata/RHSA-2026:2074
- https://access.redhat.com/errata/RHSA-2026:2220
- https://access.redhat.com/errata/RHSA-2026:2231
- https://access.redhat.com/errata/RHSA-2026:2271
- https://access.redhat.com/errata/RHSA-2026:2286
- https://access.redhat.com/security/cve/CVE-2026-0878
- https://bugzilla.redhat.com/show_bug.cgi?id=2428965
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.