CVE-2026-84142: Internally found bugs fixed in Firefox 155
Internally found bugs present in Firefox 154. Some of these bugs showed evidence of memory corruption or another security-relevant defect and we presume that with enough effort some of these could have been exploited.
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
Mozilla Firefoxto 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
Frequently Asked Questions
Which Firefox versions are affected and which version contains the fix?
The issues were present in Firefox 154 and were fixed in Firefox 155.
Is exploitation confirmed?
No exploitation is confirmed in the provided information. Mozilla reported that some internally found bugs showed evidence of memory corruption or another security-relevant defect and could potentially have been exploited with sufficient effort.