9.6
CRITICAL
CVSS 3.1
CVE-2026-12294
Sandbox escape in the DOM: Workers component
Overview
Description
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.
Details
INFO
Published Date :
June 16, 2026, 1:16 p.m.
Last Modified :
June 30, 2026, 1:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework
for assessing the severity of vulnerabilities in software and systems.
We collect and displays CVSS scores from various sources for each CVE.
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | ||||
| CVSS 3.1 | HIGH | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c |
Solution
Update Firefox to a patched version to fix the sandbox escape vulnerability.
- Update Firefox to version 152 or later.
- Update Firefox ESR to version 140.12 or later.
- Update Firefox ESR to version 115.37 or later.
References
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-12294.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-12294 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-12294
weaknesses.
CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs Accessing Functionality Not Properly Constrained by ACLs
CAPEC-17: Using Malicious Files Using Malicious Files
CAPEC-20: Encryption Brute Forcing Encryption Brute Forcing
CAPEC-22: Exploiting Trust in Client Exploiting Trust in Client
CAPEC-36: Using Unpublished Interfaces or Functionality Using Unpublished Interfaces or Functionality
CAPEC-51: Poison Web Service Registry Poison Web Service Registry
CAPEC-57: Utilizing REST's Trust in the System Resource to Obtain Sensitive Data Utilizing REST's Trust in the System Resource to Obtain Sensitive Data
CAPEC-59: Session Credential Falsification through Prediction Session Credential Falsification through Prediction
CAPEC-65: Sniff Application Code Sniff Application Code
CAPEC-74: Manipulating State Manipulating State
CAPEC-87: Forceful Browsing Forceful Browsing
CAPEC-107: Cross Site Tracing Cross Site Tracing
CAPEC-127: Directory Indexing Directory Indexing
CAPEC-237: Escaping a Sandbox by Calling Code in Another Language Escaping a Sandbox by Calling Code in Another Language
CAPEC-477: Signature Spoofing by Mixing Signed and Unsigned Content Signature Spoofing by Mixing Signed and Unsigned Content
CAPEC-480: Escaping Virtualization Escaping Virtualization
CAPEC-668: Key Negotiation of Bluetooth Attack (KNOB) Key Negotiation of Bluetooth Attack (KNOB)
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-12294 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-12294 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Reference https://access.redhat.com/errata/RHSA-2026:33445 Changed Affected [{'cpes': ['cpe:/o:redhat:enterprise_linux:10.2'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 10)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:8::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 8)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:9::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 9)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:6'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 6', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}] [{'cpes': ['cpe:/o:redhat:enterprise_linux:10.2'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 10)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:8::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 8)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:9::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 9)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:6'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 6', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'affected'}] -
CVE Modified by 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Jun. 30, 2026
Action Type Old Value New Value Added Affected [{'cpes': ['cpe:/o:redhat:enterprise_linux:10.2'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 10)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:8::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 8)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/a:redhat:enterprise_linux:9::appstream'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux AppStream (v. 9)', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:10'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 10', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:6'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 6', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:7'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 7', 'defaultStatus': 'affected'}, {'cpes': ['cpe:/o:redhat:enterprise_linux:8'], 'vendor': 'Red Hat', 'product': 'Red Hat Enterprise Linux 8', 'defaultStatus': 'affected'}] Added CVSS V3.1 AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H Added CWE CWE-266 Added Reference https://access.redhat.com/errata/RHSA-2026:27717 Added Reference https://access.redhat.com/errata/RHSA-2026:27733 Added Reference https://access.redhat.com/errata/RHSA-2026:27734 Added Reference https://access.redhat.com/errata/RHSA-2026:29940 Added Reference https://access.redhat.com/errata/RHSA-2026:30846 Added Reference https://access.redhat.com/security/cve/CVE-2026-12294 Added Reference https://bugzilla.redhat.com/show_bug.cgi?id=2489207 Added Reference https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-12294.json -
Initial Analysis by [email protected]
Jun. 18, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* versions up to (excluding) 152.0.0 *cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* versions up to (excluding) 115.37.0 *cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:* versions up to (excluding) 152.0.0 *cpe:2.3:a:mozilla:thunderbird:*:*:*:*:esr:*:*:* versions up to (excluding) 140.12.0 *cpe:2.3:a:mozilla:firefox:*:*:*:*:esr:*:*:* versions from (including) 128.0 up to (excluding) 140.12.0 Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=2039873 Types: Permissions Required Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-57/ Types: Vendor Advisory Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-58/ Types: Vendor Advisory Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-59/ Types: Vendor Advisory Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-60/ Types: Vendor Advisory Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-61/ Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H Added CWE CWE-693 Added SSVC {'id': 'CVE-2026-12294', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-18T14:23:00.636355Z'} -
CVE Modified by [email protected]
Jun. 17, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '115.37', 'versionType': 'rpm', 'lessThanOrEqual': '115.*'}, {'status': 'unaffected', 'version': '140.12', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '152', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}, {'vendor': 'Mozilla', 'product': 'Thunderbird', 'versions': [{'status': 'unaffected', 'version': '140.12', 'versionType': 'rpm', 'lessThanOrEqual': '140.*'}, {'status': 'unaffected', 'version': '152', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}] -
CVE Modified by [email protected]
Jun. 16, 2026
Action Type Old Value New Value Changed Description Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37. 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. Added Reference https://www.mozilla.org/security/advisories/mfsa2026-60/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-61/ -
New CVE Received by [email protected]
Jun. 16, 2026
Action Type Old Value New Value Added Description Sandbox escape in the DOM: Workers component. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, and Firefox ESR 115.37. Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2039873 Added Reference https://www.mozilla.org/security/advisories/mfsa2026-57/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-58/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-59/
EPSS is a daily estimate of the probability of exploitation activity
being observed over the next 30 days. Following chart shows the EPSS
score history of the vulnerability.