SEPTEMBER 15, 2026
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Case File

CVE-2026-84143

CRITICAL · CVSS 9.8 EPSS 0.38% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-09-01 · Last synced 2026-09-15

CyberRota Analysis

AI-Generated

Firefox versions 154, ESR 153.1, and ESR 140.14 contain internal bugs that may lead to memory corruption and other security-related issues, potentially allowing for exploitation. Users and organizations relying on these affected versions should prioritize upgrading to Firefox 155 or the respective ESR updates to mitigate any risks associated with these vulnerabilities.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-84143
Severity
CRITICAL
CVSS
9.8
EPSS
0.38%
Firefox

Original NVD Description

Internally found bugs present in Thunderbird 154, Thunderbird ESR 153.1 and Thunderbird ESR 140.14. 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. This vulnerability was fixed in Firefox 155, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2.

Related CVEs

Other vulnerabilities affecting the same vendor(s)