CVE-2026-74946
published 2026-08-18CVE-2026-74946: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR…
PriorityP346high8.8CVSS 3.1
AVNACLPRNUIRSUCHIHAH
EPSS
0.33%
25.4th percentile
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1.
Affected
16 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 154 | Firefox 154 |
| mozilla | firefox | < 115.39.0 | 115.39.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 116.0 < 140.14.0 | 140.14.0 |
| mozilla | firefox | >= 141.0 < 153.1.0 | 153.1.0 |
| mozilla | firefox_esr | < Firefox ESR 153.1 | Firefox ESR 153.1 |
| mozilla | firefox_esr | < Firefox ESR 140.14 | Firefox ESR 140.14 |
| mozilla | firefox_esr | < Firefox ESR 115.39 | Firefox ESR 115.39 |
| mozilla | thunderbird | < Thunderbird 154 | Thunderbird 154 |
| mozilla | thunderbird | < Thunderbird 153.1 | Thunderbird 153.1 |
| mozilla | thunderbird | < Thunderbird 140.14 | Thunderbird 140.14 |
| mozilla | thunderbird | < 140.14.0 | 140.14.0 |
| mozilla | thunderbird | — | — |
| mozilla | thunderbird | >= 141.0 < 153.1.0 | 153.1.0 |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.18.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat8.8HIGH
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Red Hat
firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
vendor_redhat·2026-08-18·CVSS 8.8
CVE-2026-74946 [HIGH] CWE-787 firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
firefox: thunderbird: Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Statement: Red Hat Product Security rates the severity of this flaw as determined by the Mozilla Foundation Security Advisory.
Package: firefox (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/firefox-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: rhel10/thunderbird-flatpak (Red Hat Enterprise Linux 10) - Affected
Package: thunderbird (Red Hat Enterprise Linux 10) - Affected
Package: firefox (Red Hat Enterprise Linux 6) - Out of suppor
Mozilla
Mozilla Foundation Security Advisory 2026-77: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-77: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-77
CVE: CVE-2026-74946
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-76: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-76: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-76
CVE: CVE-2026-74946
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-78: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-78: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-78
CVE: CVE-2026-74946
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 154
Mozilla
Mozilla Foundation Security Advisory 2026-80: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-80: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-80
CVE: CVE-2026-74946
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-75: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-75: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-75
CVE: CVE-2026-74946
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.39
Mozilla
Mozilla Foundation Security Advisory 2026-79: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-79: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-79
CVE: CVE-2026-74946
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-74: CVE-2026-74946
vendor_mozilla
CVE-2026-74946 Mozilla Foundation Security Advisory 2026-74: CVE-2026-74946
Mozilla Foundation Security Advisory 2026-74
CVE: CVE-2026-74946
Product: Firefox
Impact: high
Fixed in: Firefox 154
VulDB
Mozilla Firefox up to 115.38/140.13/153/153.0 CanvasWebGL privileges management
vuldb·2026-08-23·CVSS 8.8
CVE-2026-74946 [HIGH] Mozilla Firefox up to 115.38/140.13/153/153.0 CanvasWebGL privileges management
A vulnerability, which was classified as critical, has been found in Mozilla Firefox up to 115.38/140.13/153/153.0. This vulnerability affects unknown code of the component CanvasWebGL. Performing a manipulation results in improper privilege management.
This vulnerability is identified as CVE-2026-74946. The attack can be initiated remotely. There is not any exploit available.
It is advisable to upgrade the affected component.
GHSA
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component.
ghsa_unreviewed·2026-08-18
CVE-2026-74946 [HIGH] CWE-119 Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component.
Privilege escalation due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, and Firefox ESR 153.1.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2059997https://www.mozilla.org/security/advisories/mfsa2026-74/https://www.mozilla.org/security/advisories/mfsa2026-75/https://www.mozilla.org/security/advisories/mfsa2026-76/https://www.mozilla.org/security/advisories/mfsa2026-77/https://www.mozilla.org/security/advisories/mfsa2026-78/https://www.mozilla.org/security/advisories/mfsa2026-79/https://www.mozilla.org/security/advisories/mfsa2026-80/
2026-08-18
Published