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Fencer Vulns
critical 9.8

CVE-2021-4127 json

An out of date graphics library (Angle) likely contained vulnerabilities that could potentially be exploited.

published 2022-12-22 3 y ago modified 2026-06-17 4 mo ago also EUVD-2021-34001

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 61%
public exploits
0
none known

Summary

An out of date graphics library (Angle) likely contained vulnerabilities that could potentially be exploited. This vulnerability affects Thunderbird < 78.9 and Firefox ESR < 78.9.

Patch / fix

  • Mozilla Thunderbird 78.9
  • Mozilla Firefox ESR 78.9
  • firefox-esr Debian 14, Debian 13, Debian 12 78.9.0esr-1
  • thunderbird Debian 14, Debian 13, Debian 12 1:78.9.0-1

debian advisories DEBIAN-CVE-2021-4127

  • thunderbird RHEL 7 78.9.0-3.el7_9
  • firefox RHEL 7 78.9.0-1.el7_9
  • thunderbird RHEL 8 78.9.0-3.el8_3
  • firefox RHEL 8 78.9.0-1.el8_3
  • firefox RHEL 8.1 EUS 78.9.0-1.el8_1
  • thunderbird RHEL 8.2 EUS 78.9.0-3.el8_2
  • thunderbird RHEL 8.1 EUS 78.9.0-3.el8_1
  • firefox RHEL 8.2 EUS 78.9.0-1.el8_2

red hat advisories RHSA-2021:0996RHSA-2021:0991RHSA-2021:0994RHSA-2021:0992RHSA-2021:0995RHSA-2021:0993

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-2021-4127 updated cvss 9.8

Mozilla: Angle graphics library out of date

  • Red Hat Enterprise Linux 6 firefox, thunderbird
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) firefox 78.9.0-1.el8_3, thunderbird 78.9.0-3.el8_3
    fixed: vendor fix RHSA-2021:0990
  • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox 78.9.0-1.el8_1, thunderbird 78.9.0-3.el8_1
    fixed: vendor fix RHSA-2021:0991
  • Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox 78.9.0-1.el8_2, thunderbird 78.9.0-3.el8_2
    fixed: vendor fix RHSA-2021:0989
  • Red Hat Enterprise Linux Client (v. 7) firefox 78.9.0-1.el7_9, thunderbird 78.9.0-3.el7_9 Red Hat Enterprise Linux Client Optional (v. 7) firefox 78.9.0-1.el7_9 Red Hat Enterprise Linux Server (v. 7) firefox 78.9.0-1.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) firefox 78.9.0-1.el7_9, thunderbird 78.9.0-3.el7_9 Red Hat Enterprise Linux Workstation (v. 7) firefox 78.9.0-1.el7_9, thunderbird 78.9.0-3.el7_9 Red Hat Enterprise Linux Workstation Optional (v. 7) firefox 78.9.0-1.el7_9
    fixed: vendor fix RHSA-2021:0992

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
partial
Assessed
18 mo ago

Exploit prediction

0.95% chance of exploitation in the next 30 days, higher than 61% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • bugzilla.mozilla.org https://bugzilla.mozilla.org/show_bug.cgi?id=1691547 referenced PoC, tagged "exploit" by a source, unverified

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
NVD 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 Thunderbird
  • Mozilla Firefox ESR

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.