CVE•Published 2026-09-01•Modified 2026-09-03•1 article on news•4 live references•NVD data
CVE-2026-84639Mozilla · Thunderbird
Vulnerability data via NVD (ingested)
CVSS v3.1
9.1
CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
EPSS percentile
4
Exploit Prediction Scoring System · top 96% of all CVEs
Weaknesses (CWE)
Description
Triggering an error condition in certain MIME bodies would cause uninitialized memory to be used. This vulnerability was fixed in 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-2026-84639Hosts Shodan has explicitly fingerprinted as vulnerable.
Shodan · product
product:"Mozilla Thunderbird"All exposed Mozilla Thunderbird instances — cross-reference with the CVE's affected-version range.
Shodan · banner/body mention
http.html:"Thunderbird"HTTP body or banner mentions "Thunderbird" — catches deploys Shodan didn't identify as a product.
More intel sources (5)
Shodan report
vuln:CVE-2026-84639Country / ASN / product breakdown for the vuln query.
Censys
vulnerabilities.cve_id: CVE-2026-84639Censys host search filtered to this CVE id.
grep.app
CVE-2026-84639Public source-code mentions — fast PoC discovery.
GitHub code
CVE-2026-84639GitHub code search for direct mentions.
Google dork
"CVE-2026-84639" exploit -site:nvd.nist.govWrite-ups and news, NVD excluded.