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TI-2021-10584 Aliases CVE-2021-29967GHSA-xcvm-2qxh-c4v3

Out-of-bounds write in Mozilla Thunderbird

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: 9 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 88 and Firefox ESR 78.11. 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 Thunderbird < 78.11, Firefox < 89, and Firefox ESR < 78.11.

Why it matters now

EPSS 0.01368 72nd percentileScored 2026-11-07
Fix Partial Thunderbird (Mozilla): 78.11Firefox (Mozilla): 89+1 more productRed Hat: 8 advisoriesRed Hat: 9 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
MozillaThunderbirdbefore 78.1178.11Patch availableCNA
MozillaFirefoxbefore 8989Patch availableCNA
MozillaFirefox ESRbefore 78.1178.11Patch availableCNA
  • Thunderbird VendorMozilla Affected before 78.11 Fixed in 78.11 Patch available CNA
  • Firefox VendorMozilla Affected before 89 Fixed in 89 Patch available CNA
  • Firefox ESR VendorMozilla Affected before 78.11 Fixed in 78.11 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 89.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*before 78.11VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.11VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 89.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 78.11 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.11 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.11
  • Fix · CNA Firefox (Mozilla) Fixed in 89
  • Fix · CNA Firefox ESR (Mozilla) Fixed in 78.11

Red Hat 8 advisories

  • RHSA-2021:2264 Released 2021-06-07 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.11.0-1.el8_4
  • RHSA-2021:2263 Released 2021-06-07 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.11.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.11.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.11.0-1.el7_9
  • RHSA-2021:2261 Released 2021-06-07 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.11.0-1.el8_2
Show 5 more Red Hat advisories
  • RHSA-2021:2262 Released 2021-06-07 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.11.0-1.el8_1
  • RHSA-2021:2233 Released 2021-06-03 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-78.11.0-3.el8_4
  • RHSA-2021:2214 Released 2021-06-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-78.11.0-3.el8_1
  • RHSA-2021:2206 Released 2021-06-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux Client (v. 7) firefox-78.11.0-3.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) firefox-78.11.0-3.el7_9
    • Red Hat Enterprise Linux Server (v. 7) firefox-78.11.0-3.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) firefox-78.11.0-3.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) firefox-78.11.0-3.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-78.11.0-3.el7_9
  • RHSA-2021:2208 Released 2021-06-02 · Red Hat rating Important
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox-78.11.0-3.el8_2

Fixed in the same release

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

  • Release ·

    Mozilla Firefox 89

    5 records Highest priority Priority MEDIUM 1 MEDIUM, 4 LOW

    Other records, highest priority first

    • TI-2021-10581 Out-of-bounds read in Mozilla ThunderbirdPriority LOW 33
    • TI-2021-10582 A malicious website that causes an HTTP Authentication dialog to be spawned could trick…Priority LOW 25
    • TI-2021-10579 Firefox for Android would become unstable and hard-to-recover when a website opened too…Priority LOW 21
    Show all 5 records →
  • Release ·

    Mozilla Firefox ESR, Thunderbird 78.11

    2 records Highest priority Priority MEDIUM 1 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2021-10581 Out-of-bounds read in Mozilla ThunderbirdPriority LOW 33
    Show all 2 records →

Vendor assessments

Red Hat

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

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux AppStream (v. 8)Fixed RHSA-2021:2233, RHSA-2021:2264
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:2214, RHSA-2021:2262
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:2208, RHSA-2021:2261
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:2206, RHSA-2021:2263
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:2206
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:2206
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:2206, RHSA-2021:2263
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:2206, RHSA-2021:2263
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2021:2206

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-29967
  2. 2026-10-03 Alias added: GHSA-xcvm-2qxh-c4v3

References

Advisory 5

  • 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