CVE-2026-84124

Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Score

CVSS 3.1 5.4 Medium

Status

Analyzed - security@mozilla.org

Published

2026-09-01

Last modified

2026-09-01

Weaknesses

CWE-416

Affected products

• Firefox (Mozilla)
• Thunderbird (Mozilla)

References

• https://bugzilla.mozilla.org/show_bug.cgi?id=2061110
• https://www.mozilla.org/security/advisories/mfsa2026-82/
• https://www.mozilla.org/security/advisories/mfsa2026-84/
• https://www.mozilla.org/security/advisories/mfsa2026-85/
• https://www.mozilla.org/security/advisories/mfsa2026-86/
• https://www.mozilla.org/security/advisories/mfsa2026-87/
• https://www.mozilla.org/security/advisories/mfsa2026-88/