CVE-2026-84124: Use-after-free in the DOM: Core & HTML component
Use-after-free in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, and Firefox ESR 153.2.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 155 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 140.15 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 153.2 - Upgrade
Upgrade
Mozilla Firefoxto a version that resolves this vulnerability.Fixed in 155 - Upgrade
Upgrade
Mozilla Firefox ESRto a version that resolves this vulnerability.Fixed in 140.15 - Upgrade
Upgrade
Mozilla Firefox ESRto a version that resolves this vulnerability.Fixed in 153.2
Event History
Parent advisories
This vulnerability appears in the following advisories.
Peer vulnerabilities
Found alongside the following vulnerabilities.
- CVE-2026-84117
- CVE-2026-84118
- CVE-2026-84119
- CVE-2026-84120
- CVE-2026-84121
- CVE-2026-84122
- CVE-2026-84123
- CVE-2026-84124
- CVE-2026-84125
- CVE-2026-84126
- CVE-2026-84127
- CVE-2026-84128
- CVE-2026-84129
- CVE-2026-84130
- CVE-2026-84131
- CVE-2026-84132
- CVE-2026-84133
- CVE-2026-84134
- CVE-2026-84135
- CVE-2026-84136
- CVE-2026-84137
- CVE-2026-84138
- CVE-2026-84139
- CVE-2026-84140
- CVE-2026-84141
- CVE-2026-84142
- CVE-2026-84143
- CVE-2026-84144
- CVE-2026-84145
- CVE-2026-75874
- CVE-2026-16365
- CVE-2026-16371
- CVE-2026-74952
Frequently Asked Questions
Which Firefox releases contain the fix?
The issue was fixed in Firefox 155, Firefox ESR 140.15, and Firefox ESR 153.2.
Which Mozilla products should be reviewed for exposure?
Review deployments of Mozilla Firefox and Mozilla Firefox ESR, particularly ESR installations that have not reached 140.15 or 153.2.