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TI-2021-06294 Aliases CVE-2021-23973GHSA-jw3c-jgq3-cf92

Information disclosure through error messages in Mozilla Firefox

Priority LOW 32CWE-209Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Information disclosure
Confidentiality · integrity · availability
High · None · None
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-209.

Summary

When trying to load a cross-origin resource in an audio/video context a decoding error may have resulted, and the content of that error may have revealed information about the resource. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.

Why it matters now

EPSS 0.01368 72nd percentileScored 2026-11-07
Fix Partial Firefox (Mozilla): 86Thunderbird (Mozilla): 78.8+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
MozillaFirefoxbefore 8686Patch availableCNA
MozillaThunderbirdbefore 78.878.8Patch availableCNA
MozillaFirefox ESRbefore 78.878.8Patch availableCNA
  • Firefox VendorMozilla Affected before 86 Fixed in 86 Patch available CNA
  • Thunderbird VendorMozilla Affected before 78.8 Fixed in 78.8 Patch available CNA
  • Firefox ESR VendorMozilla Affected before 78.8 Fixed in 78.8 Patch available CNA

CPE configurations NVD · 5

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*before 86.0VulnerableMozilla
cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*before 78.8VulnerableMozilla
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*before 78.8VulnerableMozilla
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*9.0VulnerableDebian
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*10.0VulnerableDebian
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:* Versions before 86.0 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:* Versions before 78.8 Vulnerable ·Mozilla
  • cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:* Versions before 78.8 Vulnerable ·Mozilla
  • cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* Versions 9.0 Vulnerable ·Debian
  • cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* Versions 10.0 Vulnerable ·Debian

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 86
  • Fix · CNA Thunderbird (Mozilla) Fixed in 78.8
  • Fix · CNA Firefox ESR (Mozilla) Fixed in 78.8

Red Hat 8 advisories

  • RHSA-2021:0661 Released 2021-02-24 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux Client (v. 7) thunderbird-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) thunderbird-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) thunderbird-78.8.0-1.el7_9
  • RHSA-2021:0656 Released 2021-02-24 · Red Hat rating Critical
    firefox security update
    • Red Hat Enterprise Linux Client (v. 7) firefox-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Client Optional (v. 7) firefox-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Server (v. 7) firefox-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Server Optional (v. 7) firefox-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Workstation (v. 7) firefox-78.8.0-1.el7_9
    • Red Hat Enterprise Linux Workstation Optional (v. 7) firefox-78.8.0-1.el7_9
  • RHSA-2021:0662 Released 2021-02-24 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) thunderbird-78.8.0-1.el8_2
Show 5 more Red Hat advisories
  • RHSA-2021:0660 Released 2021-02-24 · Red Hat rating Critical
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.2) firefox-78.8.0-1.el8_2
  • RHSA-2021:0658 Released 2021-02-24 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) thunderbird-78.8.0-1.el8_1
  • RHSA-2021:0657 Released 2021-02-24 · Red Hat rating Important
    thunderbird security update
    • Red Hat Enterprise Linux AppStream (v. 8) thunderbird-78.8.0-1.el8_3
  • RHSA-2021:0659 Released 2021-02-24 · Red Hat rating Critical
    firefox security update
    • Red Hat Enterprise Linux AppStream EUS (v. 8.1) firefox-78.8.0-1.el8_1
  • RHSA-2021:0655 Released 2021-02-24 · Red Hat rating Critical
    firefox security update
    • Red Hat Enterprise Linux AppStream (v. 8) firefox-78.8.0-1.el8_3

Fixed in the same release

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

  • Advisory ·

    Mozilla Firefox, Firefox ESR, Thunderbird — GLSA-202104-10

    12 records Highest priority Priority MEDIUM 2 MEDIUM, 10 LOW

    Other records, highest priority first

    • TI-2021-06299 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 41
    • TI-2021-06293 One phishing tactic on the web is to provide a link with HTTP Auth.Priority MEDIUM 40
    • TI-2021-06297 Clickjacking in Mozilla FirefoxPriority LOW 37
    Show all 12 records → Advisory →
  • Advisory ·

    Mozilla Firefox, Firefox ESR, Thunderbird — GLSA-202104-09

    5 records Highest priority Priority MEDIUM 1 MEDIUM, 4 LOW

    Other records, highest priority first

    • TI-2021-06299 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 41
    • TI-2021-06284 Further techniques that built on the slipstream research combined with a malicious…Priority LOW 35
    • TI-2021-06289 Information disclosure through error messages in Mozilla FirefoxPriority LOW 23
    Show all 5 records → Advisory →
Show 1 more group
  • Advisory ·

    Mozilla Firefox, Firefox ESR, Thunderbird — DSA-4866

    4 records Highest priority Priority MEDIUM 1 MEDIUM, 3 LOW

    Other records, highest priority first

    • TI-2021-06299 Out-of-bounds write in Mozilla FirefoxPriority MEDIUM 41
    • TI-2021-06289 Information disclosure through error messages in Mozilla FirefoxPriority LOW 23
    • TI-2021-06290 As specified in the W3C Content Security Policy draft, when creating a violation report…Priority LOW 22
    Show all 4 records → Advisory →

Vendor assessments

Red Hat

Red Hat rating: Low. 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-2021:0655, RHSA-2021:0657
Red Hat Enterprise Linux AppStream EUS (v. 8.1)Fixed RHSA-2021:0658, RHSA-2021:0659
Red Hat Enterprise Linux AppStream EUS (v. 8.2)Fixed RHSA-2021:0660, RHSA-2021:0662
Red Hat Enterprise Linux Client (v. 7)Fixed RHSA-2021:0656, RHSA-2021:0661
Red Hat Enterprise Linux Client Optional (v. 7)Fixed RHSA-2021:0656
Red Hat Enterprise Linux Server (v. 7)Fixed RHSA-2021:0656
Red Hat Enterprise Linux Server Optional (v. 7)Fixed RHSA-2021:0656, RHSA-2021:0661
Red Hat Enterprise Linux Workstation (v. 7)Fixed RHSA-2021:0656, RHSA-2021:0661
Red Hat Enterprise Linux Workstation Optional (v. 7)Fixed RHSA-2021:0656

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-23973
  2. 2026-10-03 Alias added: GHSA-jw3c-jgq3-cf92

References

Advisory 8

  • 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