CVE-2025-2857 Affecting firefox-esr package, versions <136.0.4-r0
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CHAINGUARDLATEST-FIREFOXESR-17765011
- published1 Jul 2026
- disclosed27 Mar 2025
Introduced: 27 Mar 2025
CVE-2025-2857 (opens in a new tab)How to fix?
Upgrade Chainguard firefox-esr to version 136.0.4-r0 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Chainguard.
See How to fix? for Chainguard relevant fixed versions and status.
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.