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Fencer Intel
high 7.5

CVE-2026-4684 json

Race condition, use-after-free in the Graphics: WebRender component

published 7mo ago modified 3mo ago also EUVD-2026-14792

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Race condition, use-after-free in the Graphics: WebRender component. This vulnerability was fixed in Firefox 149, Firefox ESR 115.34, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.

Patch / fix

  • Red Hat Red Hat Enterprise Linux 10 0:140.9.0-1.el10_1
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support 0:140.9.0-1.el10_0
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support 0:140.9.0-1.el7_9
  • Red Hat Red Hat Enterprise Linux 8 0:140.9.0-1.el8_10
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support 0:140.9.0-1.el8_2
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support 0:140.9.0-1.el8_4
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On 0:140.9.0-1.el8_4
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support 0:140.9.0-1.el8_6
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service 0:140.9.0-1.el8_6
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions 0:140.9.0-1.el8_6
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service 0:140.9.0-1.el8_8
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions 0:140.9.0-1.el8_8
  • Red Hat Red Hat Enterprise Linux 9 0:140.9.0-1.el9_7
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions 0:140.9.0-1.el9_0
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions 0:140.9.0-1.el9_2
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support 0:140.9.0-1.el9_4
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support 0:140.9.0-1.el9_6
  • firefox-esr Debian 12 140.9.0esr-1~deb12u1
  • firefox-esr Debian 13 140.9.0esr-1~deb13u1
  • firefox-esr Debian 14 140.9.0esr-1
  • thunderbird Debian 12 1:140.9.0esr-1~deb12u1
  • thunderbird Debian 13 1:140.9.0esr-1~deb13u1
  • thunderbird Debian 14 1:140.9.0esr-1

debian advisories DEBIAN-CVE-2026-4684

  • thunderbird RHEL 8 140.9.0-1.el8_10
  • thunderbird RHEL 10.1 140.9.0-1.el10_1
  • thunderbird RHEL 9 140.9.0-1.el9_7
  • firefox RHEL 10.1 140.9.0-1.el10_1
  • firefox RHEL 8 140.9.0-1.el8_10
  • firefox RHEL 9 140.9.0-1.el9_7
  • firefox-x11 RHEL 9 140.9.0-1.el9_7
  • thunderbird RHEL 8.4 EUS_LONG_LIFE, RHEL 8.4 AUS 140.9.0-1.el8_4

red hat advisories RHSA-2026:8850RHSA-2026:8427RHSA-2026:8315RHSA-2026:8289RHSA-2026:8290RHSA-2026:8287

  • MozillaThunderbird openSUSE Leap 15.6 140.9.0-150200.8.263.1
  • MozillaFirefox SLES for SAP applications 16.0, SLES 16.0 140.9.0-160000.1.1
  • MozillaFirefox SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +9 more 140.9.0-150200.152.225.1
  • MozillaFirefox SLES LTSS Extended Security 12 SP5, SLES 12 SP5-LTSS 140.9.0-112.304.2

suse advisories SUSE-SU-2026:1163-1SUSE-SU-2026:20978-1SUSE-SU-2026:1127-1SUSE-SU-2026:1126-1

  • MozillaFirefox openSUSE Tumbleweed 149.0-1.1
  • MozillaThunderbird openSUSE Tumbleweed 140.9.0-1.1
  • MozillaFirefox openSUSE Leap 16.0 140.9.0-160000.1.1
  • firefox-esr openSUSE Tumbleweed 140.9.0-1.1

opensuse advisories openSUSE-SU-2026:10458-1openSUSE-SU-2026:10447-1openSUSE-SU-2026:20439-1openSUSE-SU-2026:10413-1

  • thunderbird AlmaLinux 8 140.9.0-1.el8_10.alma.1
  • thunderbird AlmaLinux 10 140.9.0-1.el10_1.alma.1
  • thunderbird AlmaLinux 9 140.9.0-1.el9_7.alma.1
  • firefox AlmaLinux 9 140.9.0-1.el9_7.alma.1
  • firefox-x11 AlmaLinux 9 140.9.0-1.el9_7.alma.1
  • firefox AlmaLinux 10 140.9.0-1.el10_1
  • firefox AlmaLinux 8 140.9.0-1.el8_10.alma.1

almalinux advisories ALSA-2026:6917ALSA-2026:6342ALSA-2026:6188ALSA-2026:5930ALSA-2026:5931ALSA-2026:5932

  • thunderbird Rocky Linux 8 140.9.0-1.el8_10
  • firefox Rocky Linux 10 140.9.0-1.el10_1
  • thunderbird Rocky Linux 10 140.9.0-1.el10_1
  • firefox Rocky Linux 9 140.9.0-1.el9_7
  • thunderbird Rocky Linux 9 140.9.0-1.el9_7
  • firefox Rocky Linux 8 140.9.0-1.el8_10

rocky linux advisories RLSA-2026:6917RLSA-2026:5931RLSA-2026:6342RLSA-2026:5930RLSA-2026:6188RLSA-2026:5932

Is CVE-2026-4684 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-2026-4684 updated cvss 7.5

firefox: thunderbird: Race condition, use-after-free in the Graphics: WebRender component

  • Red Hat Enterprise Linux 6 firefox, thunderbird Red Hat Enterprise Linux 7 thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 10 rhel10/firefox-flatpak, rhel10/thunderbird-flatpak
    affected: no fix available
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 140.9.0-1.el8_10, thunderbird 140.9.0-1.el8_10
    fixed: vendor fix RHSA-2026:5932
  • Red Hat Enterprise Linux AppStream (v. 9) firefox 140.9.0-1.el9_7, firefox-x11 140.9.0-1.el9_7, thunderbird 140.9.0-1.el9_7
    fixed: vendor fix RHSA-2026:5930
  • Red Hat Enterprise Linux AppStream (v. 10) firefox 140.9.0-1.el10_1, thunderbird 140.9.0-1.el10_1
    fixed: vendor fix RHSA-2026:5931
  • Red Hat Enterprise Linux AppStream AUS (v. 8.2) firefox 140.9.0-1.el8_2, thunderbird 140.9.0-1.el8_2
    fixed: vendor fix RHSA-2026:7840
  • Red Hat Enterprise Linux AppStream AUS (v.8.4) firefox 140.9.0-1.el8_4, thunderbird 140.9.0-1.el8_4
    fixed: vendor fix RHSA-2026:7858
  • Red Hat Enterprise Linux AppStream AUS (v.8.6) firefox 140.9.0-1.el8_6, thunderbird 140.9.0-1.el8_6 Red Hat Enterprise Linux AppStream E4S (v.8.6) firefox 140.9.0-1.el8_6, thunderbird 140.9.0-1.el8_6
    fixed: vendor fix RHSA-2026:7842
show 10 more
  • Red Hat Enterprise Linux AppStream E4S (v.8.8) firefox 140.9.0-1.el8_8, thunderbird 140.9.0-1.el8_8
    fixed: vendor fix RHSA-2026:7838
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) firefox 140.9.0-1.el9_0, thunderbird 140.9.0-1.el9_0
    fixed: vendor fix RHSA-2026:7839
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) firefox 140.9.0-1.el9_2, firefox-x11 140.9.0-1.el9_2, thunderbird 140.9.0-1.el9_2
    fixed: vendor fix RHSA-2026:7841
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) firefox 140.9.0-1.el10_0, thunderbird 140.9.0-1.el10_0
    fixed: vendor fix RHSA-2026:7843
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) firefox 140.9.0-1.el9_4, firefox-x11 140.9.0-1.el9_4, thunderbird 140.9.0-1.el9_4
    fixed: vendor fix RHSA-2026:7845
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) firefox 140.9.0-1.el9_6, firefox-x11 140.9.0-1.el9_6, thunderbird 140.9.0-1.el9_6
    fixed: vendor fix RHSA-2026:7837
  • Red Hat Enterprise Linux AppStream EUS EXTENSION (v.8.4) firefox 140.9.0-1.el8_4, thunderbird 140.9.0-1.el8_4
    fixed: vendor fix RHSA-2026:7858
  • Red Hat Enterprise Linux AppStream TUS (v.8.6) firefox 140.9.0-1.el8_6, thunderbird 140.9.0-1.el8_6
    fixed: vendor fix RHSA-2026:7842
  • Red Hat Enterprise Linux AppStream TUS (v.8.8) firefox 140.9.0-1.el8_8, thunderbird 140.9.0-1.el8_8
    fixed: vendor fix RHSA-2026:7838
  • Red Hat Enterprise Linux Server (v. 7 ELS) firefox 140.9.0-1.el7_9
    fixed: vendor fix RHSA-2026:8427

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
7mo ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

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

Affected products

  • Mozilla Firefox
  • Mozilla Thunderbird
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 7 Extended Lifecycle Support
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On
  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service
  • Red Hat Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9
  • Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions
  • Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 9.6 Extended Update Support
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7

Classification

Weakness
  • CWE-416 Use After Free
  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
  • CWE-364 Signal Handler Race Condition

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.