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Fencer Intel
critical 10.0

CVE-2025-2857 json

Incorrect handle could lead to sandbox escapes

published last yr. modified last mo. also EUVD-2025-8495

cvss
10.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 80%
public exploits
0
none known

Summary

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.

Patch / fix

  • mozilla firefox 115.21.1, 128.8.1, 136.0.4
  • mozilla firefox_esr 115.21.1, 128.8.1, 136.0.4
  • firefox-esr openSUSE Tumbleweed 128.9.0-1.1
  • mozjs128 openSUSE Tumbleweed 128.8.1-1.1
  • MozillaFirefox openSUSE Tumbleweed 136.0.4-1.1

opensuse advisories openSUSE-SU-2025:14961-1openSUSE-SU-2025:14958-1openSUSE-SU-2025:14948-1

Is CVE-2025-2857 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-2857 updated

firefox: Firefox IPC sandbox escape on windows

  • Red Hat Enterprise Linux 6 firefox Red Hat Enterprise Linux 7 firefox Red Hat Enterprise Linux 8 firefox Red Hat Enterprise Linux 9 firefox, firefox-x11 Red Hat Enterprise Linux 10 firefox
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
last yr.

Exploit prediction

1.98% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CNA 3.1 10.0 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Affected products

  • Mozilla Firefox

Classification

Weakness
  • CWE-668 Exposure of Resource to Wrong Sphere

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.