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Fencer Intel
high 7.5

CVE-2026-8949 json

Integer overflow in the Widget: Win32 component

published 5mo ago modified 28d ago also EUVD-2026-30899

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 48%
public exploits
0
none known

Summary

Integer overflow in the Widget: Win32 component. This vulnerability was fixed in Firefox 151, Firefox ESR 140.11, Thunderbird 151, and Thunderbird 140.11.

Patch / fix

  • mozilla firefox 140.11, 151
  • mozilla firefox_esr 140.11, 151
  • mozilla thunderbird 140.11, 151
  • mozilla thunderbird_esr 140.11, 151
  • MozillaThunderbird openSUSE Leap 16.0 140.12.0-bp160.1.1
  • MozillaFirefox openSUSE Tumbleweed 151.0.1-1.1
  • MozillaThunderbird openSUSE Tumbleweed 140.11.1-1.1
  • firefox-esr openSUSE Tumbleweed 140.11.0-1.1

opensuse advisories openSUSE-SU-2026:21168-1openSUSE-SU-2026:10863-1openSUSE-SU-2026:10864-1openSUSE-SU-2026:10813-1

Is CVE-2026-8949 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.

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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-2026-8949 updated cvss 6.1

firefox: thunderbird: Integer overflow in the Widget: Win32 component

  • Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 firefox, thunderbird Red Hat Enterprise Linux 8 firefox, thunderbird Red Hat Enterprise Linux 9 firefox, firefox-x11, thunderbird Red Hat Enterprise Linux 10 firefox, thunderbird, rhel10/firefox-flatpak, rhel10/thunderbird-flatpak
    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
partial
Assessed
5mo ago

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 48% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

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.