CVE-2026-12294
published 2026-06-16CVE-2026-12294: Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and…
PriorityP347critical9.6CVSS 3.1
AVNACLPRNUIRSCCHIHAH
EPSS
0.36%
28.4th percentile
Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| mozilla | firefox | < Firefox 152 | Firefox 152 |
| mozilla | firefox | < 115.37.0 | 115.37.0 |
| mozilla | firefox | < 152.0.0 | 152.0.0 |
| mozilla | firefox | — | — |
| mozilla | firefox | >= 128.0 < 140.12.0 | 140.12.0 |
| mozilla | firefox_esr | < Firefox ESR 115.37 | Firefox ESR 115.37 |
| mozilla | firefox_esr | < Firefox ESR 140.12 | Firefox ESR 140.12 |
| mozilla | thunderbird | < Thunderbird 140.12 | Thunderbird 140.12 |
| mozilla | thunderbird | < Thunderbird 152 | Thunderbird 152 |
| mozilla | thunderbird | < 140.12.0 | 140.12.0 |
| mozilla | thunderbird | < 152.0.0 | 152.0.0 |
| mozilla | thunderbird | — | — |
| rhel10 | firefox-flatpak | — | — |
| rhel10 | thunderbird-flatpak | — | — |
CVSS provenance
nvdv3.19.6CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
vendor_redhat7.5HIGH
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Red Hat
firefox: thunderbird: Sandbox escape in the DOM: Workers component
vendor_redhat·2026-06-16·CVSS 7.5
CVE-2026-12294 [HIGH] CWE-266 firefox: thunderbird: Sandbox escape in the DOM: Workers component
firefox: thunderbird: Sandbox escape in the DOM: Workers component
Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Firefox ESR 115.37, Thunderbird 152, and Thunderbird 140.12.
A flaw was found in Firefox and Thunderbird. The Mozilla Foundation's Security Advisory describes the following issue:
Sandbox escape in the DOM: Workers 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) - Af
Mozilla
Mozilla Foundation Security Advisory 2026-59: CVE-2026-12294
vendor_mozilla
CVE-2026-12294 Mozilla Foundation Security Advisory 2026-59: CVE-2026-12294
Mozilla Foundation Security Advisory 2026-59
CVE: CVE-2026-12294
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 115.37
Mozilla
Mozilla Foundation Security Advisory 2026-58: CVE-2026-12294
vendor_mozilla
CVE-2026-12294 Mozilla Foundation Security Advisory 2026-58: CVE-2026-12294
Mozilla Foundation Security Advisory 2026-58
CVE: CVE-2026-12294
Product: Firefox ESR
Impact: high
Fixed in: Firefox ESR 140.12
Mozilla
Mozilla Foundation Security Advisory 2026-61: CVE-2026-12294
vendor_mozilla
CVE-2026-12294 Mozilla Foundation Security Advisory 2026-61: CVE-2026-12294
Mozilla Foundation Security Advisory 2026-61
CVE: CVE-2026-12294
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140.12
Mozilla
Mozilla Foundation Security Advisory 2026-60: CVE-2026-12294
vendor_mozilla
CVE-2026-12294 Mozilla Foundation Security Advisory 2026-60: CVE-2026-12294
Mozilla Foundation Security Advisory 2026-60
CVE: CVE-2026-12294
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 152
Mozilla
Mozilla Foundation Security Advisory 2026-57: CVE-2026-12294
vendor_mozilla
CVE-2026-12294 Mozilla Foundation Security Advisory 2026-57: CVE-2026-12294
Mozilla Foundation Security Advisory 2026-57
CVE: CVE-2026-12294
Product: Firefox
Impact: high
Fixed in: Firefox 152
VulDB
Mozilla Firefox up to 151 Workers sandbox (Nessus ID 321221 / WID-SEC-2026-1959)
vuldb·2026-07-03·CVSS 9.6
CVE-2026-12294 [CRITICAL] Mozilla Firefox up to 151 Workers sandbox (Nessus ID 321221 / WID-SEC-2026-1959)
A vulnerability has been found in Mozilla Firefox up to 151 and classified as critical. This vulnerability affects unknown code of the component Workers. The manipulation leads to sandbox issue.
This vulnerability is uniquely identified as CVE-2026-12294. The attack is possible to be carried out remotely. No exploit exists.
The affected component should be upgraded.
GHSA
Sandbox escape in the DOM: Workers component.
ghsa_unreviewed·2026-06-16
CVE-2026-12294 Sandbox escape in the DOM: Workers component.
Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37.
No detection rules found.
No public exploits indexed.
https://bugzilla.mozilla.org/show_bug.cgi?id=2039873https://www.mozilla.org/security/advisories/mfsa2026-57/https://www.mozilla.org/security/advisories/mfsa2026-58/https://www.mozilla.org/security/advisories/mfsa2026-59/https://www.mozilla.org/security/advisories/mfsa2026-60/https://www.mozilla.org/security/advisories/mfsa2026-61/https://access.redhat.com/errata/RHSA-2026:27717https://access.redhat.com/errata/RHSA-2026:27733https://access.redhat.com/errata/RHSA-2026:27734https://access.redhat.com/errata/RHSA-2026:29940https://access.redhat.com/errata/RHSA-2026:30846https://access.redhat.com/errata/RHSA-2026:33445https://access.redhat.com/errata/RHSA-2026:36100https://access.redhat.com/errata/RHSA-2026:36101https://access.redhat.com/errata/RHSA-2026:36102https://access.redhat.com/errata/RHSA-2026:36103https://access.redhat.com/errata/RHSA-2026:37210https://access.redhat.com/errata/RHSA-2026:37391https://access.redhat.com/errata/RHSA-2026:38506https://access.redhat.com/errata/RHSA-2026:38750https://access.redhat.com/errata/RHSA-2026:38751https://access.redhat.com/errata/RHSA-2026:38753https://access.redhat.com/security/cve/CVE-2026-12294https://bugzilla.redhat.com/show_bug.cgi?id=2489207https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12294.json
2026-06-16
Published