CVE-2026-74934
published 2026-08-18CVE-2026-74934: Site isolation issue in the Graphics: CanvasWebGL component. This vulnerability was fixed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR…
PriorityP339high7.5CVSS 3.1
AVNACHPRNUIRSUCHIHAH
EPSS
0.16%
5.3th percentile
Site isolation issue 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 140.14 | Firefox ESR 140.14 |
| mozilla | firefox_esr | < Firefox ESR 153.1 | Firefox ESR 153.1 |
| mozilla | firefox_esr | < Firefox ESR 115.39 | Firefox ESR 115.39 |
| mozilla | thunderbird | < Thunderbird 154 | Thunderbird 154 |
| mozilla | thunderbird | < Thunderbird 140.14 | Thunderbird 140.14 |
| mozilla | thunderbird | < Thunderbird 153.1 | Thunderbird 153.1 |
| 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
nvdv3.17.5HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
vendor_redhat7.5HIGH
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VulDB
Mozilla Firefox up to 115.38/140.13/153/153.0 CanvasWebGL isolation
vuldb·2026-08-23·CVSS 7.5
CVE-2026-74934 [HIGH] Mozilla Firefox up to 115.38/140.13/153/153.0 CanvasWebGL isolation
A vulnerability was found in Mozilla Firefox up to 115.38/140.13/153/153.0. It has been declared as critical. This affects an unknown function of the component CanvasWebGL. Such manipulation leads to improper isolation or compartmentalization.
This vulnerability is documented as CVE-2026-74934. The attack can be executed remotely. There is not any exploit available.
It is recommended to upgrade the affected component.
GHSA
Site isolation issue in the Graphics: CanvasWebGL component.
ghsa_unreviewed·2026-08-18
CVE-2026-74934 Site isolation issue in the Graphics: CanvasWebGL component.
Site isolation issue 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.
Red Hat
firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
vendor_redhat·2026-08-18·CVSS 7.5
CVE-2026-74934 [HIGH] CWE-653 firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Site isolation issue 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 support scope
Package: thunderbird (Red Hat Enterprise Linux 6) - Out of suppor
Mozilla
Mozilla Foundation Security Advisory 2026-76: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-76: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-76
CVE: CVE-2026-74934
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-77: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-77: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-77
CVE: CVE-2026-74934
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-78: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-78: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-78
CVE: CVE-2026-74934
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 154
Mozilla
Mozilla Foundation Security Advisory 2026-74: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-74: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-74
CVE: CVE-2026-74934
Product: Firefox
Impact: high
Fixed in: Firefox 154
Mozilla
Mozilla Foundation Security Advisory 2026-79: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-79: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-79
CVE: CVE-2026-74934
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.14
Mozilla
Mozilla Foundation Security Advisory 2026-80: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-80: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-80
CVE: CVE-2026-74934
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 153.1
Mozilla
Mozilla Foundation Security Advisory 2026-75: CVE-2026-74934
vendor_mozilla
CVE-2026-74934 Mozilla Foundation Security Advisory 2026-75: CVE-2026-74934
Mozilla Foundation Security Advisory 2026-75
CVE: CVE-2026-74934
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.39
No detection rules found.
No public exploits indexed.
Hackernews
⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
blogs_hackernews·2026-08-24
CVE-2026-19478 ⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
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## ⚡ Weekly Recap: AI-Powered PLC Attacks, GitLab Attacks, Stripe Key Leaks and More
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Bugzilla
CVE-2026-74934 firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
bugzilla·2026-08-18
CVE-2026-74934 [HIGH] CVE-2026-74934 firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
CVE-2026-74934 firefox: thunderbird: Site isolation issue in the Graphics: CanvasWebGL component
Site isolation issue 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.
https://bugzilla.mozilla.org/show_bug.cgi?id=2050584https://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