CVE-2025-2857: Vulnerability in Mozilla Firefox
Following the recent Chrome sandbox escape (CVE-2025-2783), various Firefox developers identified a similar pattern in our IPC code. A compromised child process could cause the parent process to return an unintentionally powerful handle, leading to a sandbox escape. The original vulnerability was being exploited in the wild. *This only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability was fixed in Firefox 136.0.4, Firefox ESR 128.8.1, and Firefox ESR 115.21.1.
AI Analysis
Technical Summary
CVE-2025-2857 is a sandbox escape vulnerability in Mozilla Firefox on Windows caused by IPC code flaws. A compromised child process can manipulate the parent process into returning a handle with excessive privileges, enabling escape from the sandbox environment. This vulnerability was actively exploited in the wild and was discovered after a similar sandbox escape was found in Chrome (CVE-2025-2783). The flaw affects Firefox on Windows only and has been remediated in Firefox 136.0.4 and specified ESR versions.
Potential Impact
Successful exploitation allows an attacker controlling a child process to escape the Firefox sandbox on Windows, potentially gaining elevated privileges and executing arbitrary code outside the sandbox restrictions. This compromises the security isolation intended by the sandbox, leading to full confidentiality, integrity, and availability impacts as indicated by the CVSS score of 10.
Mitigation Recommendations
This vulnerability is fixed in Firefox 136.0.4, Firefox ESR 128.8.1, and Firefox ESR 115.21.1. Users and administrators should update affected Firefox installations to these versions or later to remediate the issue. No other mitigation is required as the fix is official and available.
CVE-2025-2857: Vulnerability in Mozilla Firefox
Description
Following the recent Chrome sandbox escape (CVE-2025-2783), various Firefox developers identified a similar pattern in our IPC code. A compromised child process could cause the parent process to return an unintentionally powerful handle, leading to a sandbox escape. The original vulnerability was being exploited in the wild. *This only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability was fixed in Firefox 136.0.4, Firefox ESR 128.8.1, and Firefox ESR 115.21.1.
CVSS v3.1
Score 10.0critical
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2025-2857 is a sandbox escape vulnerability in Mozilla Firefox on Windows caused by IPC code flaws. A compromised child process can manipulate the parent process into returning a handle with excessive privileges, enabling escape from the sandbox environment. This vulnerability was actively exploited in the wild and was discovered after a similar sandbox escape was found in Chrome (CVE-2025-2783). The flaw affects Firefox on Windows only and has been remediated in Firefox 136.0.4 and specified ESR versions.
Potential Impact
Successful exploitation allows an attacker controlling a child process to escape the Firefox sandbox on Windows, potentially gaining elevated privileges and executing arbitrary code outside the sandbox restrictions. This compromises the security isolation intended by the sandbox, leading to full confidentiality, integrity, and availability impacts as indicated by the CVSS score of 10.
Mitigation Recommendations
This vulnerability is fixed in Firefox 136.0.4, Firefox ESR 128.8.1, and Firefox ESR 115.21.1. Users and administrators should update affected Firefox installations to these versions or later to remediate the issue. No other mitigation is required as the fix is official and available.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- mozilla
- Date Reserved
- 2025-03-27T10:54:42.071Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://www.mozilla.org/security/advisories/mfsa2025-19/","vendor":"Mozilla"}]
Threat ID: 6904bd22f54b4a89977ab6ca
Added to database: 10/31/2025, 13:44:02 UTC
Last enriched: 06/10/2026, 10:04:08 UTC
Last updated: 09/10/2026, 19:36:49 UTC
Views: 433
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