CVE•Published 2026-09-01•Modified 2026-09-03•1 article on news•4 live references•NVD data
CVE-2026-84143Mozilla · Firefox
Vulnerability data via NVD (ingested)
CVSS v3.1
9.8
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS percentile
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Weaknesses (CWE)
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.
Timeline
Published 2026-09-01
Modified 2026-09-03
External references
Search for exposed instances
Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).
Shodan · vuln tag0 hosts
vuln:CVE-2026-84143Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Mozilla Firefox"All exposed Mozilla Firefox instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Firefox"HTTP body or banner mentions "Firefox" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2026-84143Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-84143Censys host search filtered to this CVE id.
grep.app
CVE-2026-84143Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-84143GitHub code search for direct mentions.
Google dork
"CVE-2026-84143" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.