Read the docs
TI-2020-17831 Aliases CVE-2020-35113GHSA-65vg-v22r-h32v

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: 10 fixed, 2 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 83 and Firefox ESR 78.5. 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 < 84, Thunderbird < 78.6, and Firefox ESR < 78.6.

Why it matters now

EPSS 0.01572 75th percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 84Thunderbird (Mozilla): 78.6+1 more productRed Hat: 10 advisoriesRed Hat: 10 fixed, 2 without a fix

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 8484Patch availableCNA
MozillaThunderbirdbefore 78.678.6Patch availableCNA
MozillaFirefox ESRbefore 78.678.6Patch availableCNA
  • Firefox VendorMozilla Affected before 84 Fixed in 84 Patch available CNA
  • Thunderbird VendorMozilla Affected before 78.6 Fixed in 78.6 Patch available CNA
  • Firefox ESR VendorMozilla Affected before 78.6 Fixed in 78.6 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 84.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*before 78.6.0VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.6.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 84.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 78.6.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.6.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 84
  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.6
  • Fix · CNA Firefox ESR (Mozilla) Fixed in 78.6

Red Hat 10 advisories

  • RHSA-2020:5645 Released 2020-12-21 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream E4S (v. 8.0) thunderbird-78.6.0-1.el8_0
  • RHSA-2020:5644 Released 2020-12-21 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.6.0-1.el8_1
  • RHSA-2020:5624 Released 2020-12-17 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.6.0-1.el8_3
Show 7 more Red Hat advisories
  • RHSA-2020:5622 Released 2020-12-17 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.6.0-1.el8_2
  • RHSA-2020:5618 Released 2020-12-17 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.6.0-1.el7_9
  • RHSA-2020:5561 Released 2020-12-16 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux Client (v. 7) firefox-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) firefox-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Server (v. 7) firefox-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) firefox-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) firefox-78.6.0-1.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-78.6.0-1.el7_9
  • RHSA-2020:5563 Released 2020-12-16 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox-78.6.0-1.el8_2
  • RHSA-2020:5565 Released 2020-12-16 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream E4S (v. 8.0) firefox-78.6.0-1.el8_0
  • RHSA-2020:5562 Released 2020-12-16 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-78.6.0-1.el8_3
  • RHSA-2020:5564 Released 2020-12-16 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-78.6.0-1.el8_1

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    Mozilla Firefox 84

    13 records Highest priority Priority MEDIUM 7 MEDIUM, 6 LOW

    Other records, highest priority first

    • TI-2020-16395 Use after free in Mozilla FirefoxPriority MEDIUM 45
    • TI-2020-16394 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
    • TI-2020-17830 If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from…Priority MEDIUM 41
    Show all 13 records →
  • Release ·

    Mozilla Firefox ESR, Thunderbird 78.6

    7 records Highest priority Priority MEDIUM 5 MEDIUM, 2 LOW

    Other records, highest priority first

    • TI-2020-16394 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 42
    • TI-2020-17830 If a user downloaded a file lacking an extension on Windows, and then "Open"-ed it from…Priority MEDIUM 41
    • TI-2020-16397 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 41
    Show all 7 records →

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 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2020:5562, RHSA-2020:5624
Red Hat Enterprise Linux AppStream E4S (v. 8.0)Fixed RHSA-2020:5565, RHSA-2020:5645
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2020:5564, RHSA-2020:5644
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2020:5563, RHSA-2020:5622
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2020:5561, RHSA-2020:5618
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2020:5561
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2020:5561
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2020:5561, RHSA-2020:5618
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2020:5561, RHSA-2020:5618
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2020:5561

Timeline

  1. 2026-10-02 Threatist record created from CVE-2020-35113
  2. 2026-10-03 Alias added: GHSA-65vg-v22r-h32v

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