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TI-2021-16092 Aliases CVE-2021-38492GHSA-qq3m-5g62-2hhj

When delegating navigations to the operating system, Firefox would accept the `mk` scheme…

Priority LOW 31Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA.

Summary

When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.

Why it matters now

EPSS 0.01155 67th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed Firefox (Mozilla): 92Thunderbird (Mozilla): 91.1, 78.14+1 more product

SSVC decision points

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

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefoxbefore 9292Patch availableCNA
MozillaThunderbirdbefore 91.1; before 78.1491.1, 78.14Patch availableCNA
MozillaFirefox ESRbefore 78.14; before 91.178.14, 91.1Patch availableCNA
  • Firefox VendorMozilla Affected before 92 Fixed in 92 Patch available CNA
  • Thunderbird VendorMozilla Affected before 91.1; before 78.14 Fixed in 91.1, 78.14 Patch available CNA
  • Firefox ESR VendorMozilla Affected before 78.14; before 91.1 Fixed in 78.14, 91.1 Patch available CNA

CPE configurations NVD · 4

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 92.0; 91.0 to before 91.1VulnerableMozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*before 78.14VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.14; 91.0 to before 91.1VulnerableMozilla
cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*not specified by NVDRunning onMicrosoft
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 92.0; 91.0 to before 91.1 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 78.14 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.14; 91.0 to before 91.1 Vulnerable ·Mozilla
  • cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Microsoft

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 92
  • Fix · CNA Thunderbird (Mozilla) Fixed in 91.1, 78.14
  • Fix · CNA Firefox ESR (Mozilla) Fixed in 78.14, 91.1

Fixed in the same release

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

  • Release ·

    Mozilla Firefox 92

    5 records Highest priority Priority MEDIUM 2 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2021-16093 Out-of-bounds write in Mozilla Firefox ESRPriority MEDIUM 41
    • TI-2021-16094 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 40
    • TI-2021-10609 Firefox for Android allowed navigations through the `intent://` protocol, which could be…Priority LOW 37
    Show all 5 records →

Vendor assessments

Red Hat

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

Not affected: 3 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-38492
  2. 2026-10-03 Alias added: GHSA-qq3m-5g62-2hhj

References

Exploit 1

Advisory 6

  • 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