CVE-2026-84128: Privilege escalation in the WebDriver BiDi component
Privilege escalation in the WebDriver BiDi component. This vulnerability was fixed in Firefox 155 and Thunderbird 155.
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
Firefox/WebDriver BiDito a version that resolves this vulnerability.Fixed in 155 - Upgrade
Upgrade
Thunderbird/WebDriver BiDito a version that resolves this vulnerability.Fixed in 155
Event History
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-2026-84639
- CVE-2026-84640
- CVE-2026-84641
- CVE-2026-84642
Frequently Asked Questions
Which Firefox versions are affected?
The issue was fixed in Firefox 155. The provided information does not specify the earliest affected version or whether any Firefox variants are affected.
What should teams do to remediate this issue?
Upgrade Firefox to version 155 or later, where the vulnerability is fixed. No alternative mitigation or workaround is provided in the available information.