CVE-2026-75874
Sandbox escape in the Remote Settings Client component
Description
Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.
INFO
Published Date :
Aug. 18, 2026, 1:17 p.m.
Last Modified :
Sept. 1, 2026, 10:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | CRITICAL | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update the Remote Settings Client component.
- Apply updates to Firefox browser.
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-2026-75874.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-75874 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-2026-75874
weaknesses.
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-2026-75874 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-75874 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 [email protected]
Sep. 01, 2026
Action Type Old Value New Value Changed Description Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2. Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2. Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/75xxx/CVE-2026-75874.json">CVE-2026-75874</a> Added Reference https://www.mozilla.org/security/advisories/mfsa2026-87/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-88/ -
CVE Modified by [email protected]
Sep. 01, 2026
Action Type Old Value New Value Changed Description Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154 and Thunderbird 154. Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, and Firefox ESR 153.2. Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/75xxx/CVE-2026-75874.json">CVE-2026-75874</a> Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2039972 Added Reference https://www.mozilla.org/security/advisories/mfsa2026-74/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-78/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-83/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-84/ Added Reference https://www.mozilla.org/security/advisories/mfsa2026-85/ Removed Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2039972 Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-74/ Removed Reference https://www.mozilla.org/security/advisories/mfsa2026-78/ Removed Reference Type https://bugzilla.mozilla.org/show_bug.cgi?id=2039972 Types: Permissions Required Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-74/ Types: Vendor Advisory Removed Reference Type https://www.mozilla.org/security/advisories/mfsa2026-78/ Types: Vendor Advisory -
Initial Analysis by [email protected]
Aug. 19, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* versions up to (excluding) 154.0.0 *cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* versions up to (excluding) 154.0 Added Reference Type Mozilla Corporation: https://bugzilla.mozilla.org/show_bug.cgi?id=2039972 Types: Permissions Required Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-74/ Types: Vendor Advisory Added Reference Type Mozilla Corporation: https://www.mozilla.org/security/advisories/mfsa2026-78/ Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Aug. 18, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Added CWE CWE-693 Added SSVC {'id': 'CVE-2026-75874', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-08-18T19:23:52.490532Z'} -
CVE Modified by [email protected]
Aug. 18, 2026
Action Type Old Value New Value Changed Affected [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}] [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}, {'vendor': 'Mozilla', 'product': 'Thunderbird', 'versions': [{'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}] Changed Description Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154. Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154 and Thunderbird 154. Added Reference https://www.mozilla.org/security/advisories/mfsa2026-78/ -
New CVE Received by [email protected]
Aug. 18, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Mozilla', 'product': 'Firefox', 'versions': [{'status': 'unaffected', 'version': '154', 'versionType': 'rpm', 'lessThanOrEqual': '*'}]}] Added Description Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154. Added Reference https://bugzilla.mozilla.org/show_bug.cgi?id=2039972 Added Reference https://www.mozilla.org/security/advisories/mfsa2026-74/