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TI-2020-16391 Aliases CVE-2020-26968GHSA-84gw-f25v-grqx

Out-of-bounds write in Mozilla Firefox

Priority MEDIUM 41CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 15 fixed, 1 without a fix

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

Mozilla developers reported memory safety bugs present in Firefox 82 and Firefox ESR 78.4. 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 affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

Why it matters now

EPSS 0.01514 74th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 83Firefox ESR (Mozilla): 78.5+1 more productRed Hat: 12 advisoriesRed Hat: 15 fixed, 1 without a fix

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 8383Patch availableCNA
MozillaFirefox ESRbefore 78.578.5Patch availableCNA
MozillaThunderbirdbefore 78.578.5Patch availableCNA
  • Firefox VendorMozilla Affected before 83 Fixed in 83 Patch available CNA
  • Firefox ESR VendorMozilla Affected before 78.5 Fixed in 78.5 Patch available CNA
  • Thunderbird VendorMozilla Affected before 78.5 Fixed in 78.5 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 83.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*before 78.5VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.5VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 83.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 78.5 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.5 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 83
  • Fix · CNA Firefox ESR (Mozilla) Fixed in 78.5
  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.5

Red Hat 12 advisories

  • RHSA-2020:5314 Released 2020-12-01 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-78.5.0-1.el8_0
  • RHSA-2020:5239 Released 2020-11-30 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux Client (v. 7) firefox-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) firefox-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Server (v. 7) firefox-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) firefox-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) firefox-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-78.5.0-1.el7_9
  • RHSA-2020:5235 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.5.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.5.0-1.el7_9
Show 9 more Red Hat advisories
  • RHSA-2020:5257 Released 2020-11-30 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux Desktop (v. 6) firefox-78.5.0-1.el6_10
    • Red Hat Enterprise Linux HPC Node Optional (v. 6) firefox-78.5.0-1.el6_10
    • Red Hat Enterprise Linux Server (v. 6) firefox-78.5.0-1.el6_10
    • Red Hat Enterprise Linux Workstation (v. 6) firefox-78.5.0-1.el6_10
  • RHSA-2020:5237 Released 2020-11-30 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-78.5.0-1.el8_3
  • RHSA-2020:5238 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Desktop (v. 6) thunderbird-78.5.0-1.el6_10
    • Red Hat Enterprise Linux Server Optional (v. 6) thunderbird-78.5.0-1.el6_10
    • Red Hat Enterprise Linux Workstation (v. 6) thunderbird-78.5.0-1.el6_10
  • RHSA-2020:5234 Released 2020-11-30 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox-78.5.0-1.el8_2
  • RHSA-2020:5232 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.5.0-1.el8_2
  • RHSA-2020:5236 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.5.0-1.el8_3
  • RHSA-2020:5233 Released 2020-11-30 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-78.5.0-1.el8_1
  • RHSA-2020:5231 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.5.0-1.el8_1
  • RHSA-2020:5240 Released 2020-11-30 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-78.5.0-1.el8_0

Vendor assessments

Red Hat

Red Hat rating: Important. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 5AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2020:5236, RHSA-2020:5237
Red Hat Enterprise Linux AppStream E4S (v. 8.0)Fixed RHSA-2020:5240, RHSA-2020:5314
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2020:5231, RHSA-2020:5233
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2020:5232, RHSA-2020:5234
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2020:5235, RHSA-2020:5239
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2020:5239
Red Hat Enterprise Linux Desktop (v. 6)Fixed RHSA-2020:5238, RHSA-2020:5257
Red Hat Enterprise Linux HPC Node Optional (v. 6)Fixed RHSA-2020:5257
Red Hat Enterprise Linux Server (v. 6)Fixed RHSA-2020:5257
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:5239
Red Hat Enterprise Linux Server Optional (v. 6)Fixed RHSA-2020:5238
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2020:5235, RHSA-2020:5239
Red Hat Enterprise Linux Workstation (v. 6)Fixed RHSA-2020:5238, RHSA-2020:5257
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:5235, RHSA-2020:5239
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2020:5239

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-26968
  2. 2026-10-03 Alias added: GHSA-84gw-f25v-grqx

References

Advisory 3

Other 1

  • TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
  • TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
  • TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
  • TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
See all 3444 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences