Skip to content
Fencer Vulns
critical 9.8

CVE-2025-0247 in the critical feed json

Memory safety bugs fixed in Firefox 134 and Thunderbird 134

published 2025-01-07 22 mo ago modified 2026-10-05 34 d ago also EUVD-2025-1579

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
10.6%
EPSS 10.6% chance of exploitation in 30 days, percentile 95%
public exploits
0
none known

Summary

Memory safety bugs present in Firefox 133 and Thunderbird 133. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 134 and Thunderbird 134.

Patch / fix

  • mozilla firefox 134
  • mozilla thunderbird 134
  • firefox Ubuntu 20.04 LTS 134.0+build1-0ubuntu0.20.04.1
  • thunderbird Ubuntu 22.04 LTS 1:140.7.1+build1-0ubuntu0.22.04.1

ubuntu advisories UBUNTU-CVE-2025-0247

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • firefox-esr openSUSE Tumbleweed 153.0-1.1
  • MozillaFirefox openSUSE Tumbleweed 134.0-1.1

opensuse advisories openSUSE-SU-2026:11373-1openSUSE-SU-2025:14630-1

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-2025-0247 updated cvss 8.8

firefox: thunderbird: Memory safety bugs fixed in Firefox 134 and Thunderbird 134

  • Red Hat Enterprise Linux 6 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 firefox, thunderbird
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 firefox, thunderbird
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird Red Hat Enterprise Linux 10 firefox, thunderbird
    under investigation

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
no
Technical impact
total
Assessed
22 mo ago

Exploit prediction

10.61% chance of exploitation in the next 30 days, higher than 95% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

Classification

Weakness

References

Sources

Fencer Vulns 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.