What’s Vulnerable › Vulnerabilities

CVE-2025-2857: Incorrect handle could lead to sandbox escapes

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-03-27 · updated 2026-10-05
• Weakness: CWE-668

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.

Affected products

• Mozilla Firefox: before 136.0.4; before 115.21.1; from 128.1.0 before 128.8.1 — fixed in 115.21.1, 128.8.1, 136.0.4

How to fix

Upgrade to a fixed version: Mozilla Firefox 115.21.1, 128.8.1, 136.0.4. Check the vendor advisory for mitigations.

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=1956398
• https://issues.chromium.org/issues/405143032
• https://www.cve.org/CVERecord?id=CVE-2025-2783
• https://www.mozilla.org/security/advisories/mfsa2025-19/

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