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CVE-2026-74990 is one of a set of internally discovered security defects affecting Mozilla Thunderbird ESR 140.13, Thunderbird ESR 153.0, and Thunderbird 153. Mozilla states that the issue showed evidence of memory corruption or another security-relevant defect and assessed that, with sufficient effort, it could potentially be exploitable. Publicly available information does not identify a specific vulnerable function, code path, or component for this CVE. The issue was addressed in Thunderbird 140.14, Thunderbird 153.1, and Thunderbird 154, and corresponding Firefox fixed releases were also issued as part of the same security update cycle.
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No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
15 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A specific vulnerability affecting Debian 13 firefox-esr packages; no further technical details are provided in the content.
A specific published vulnerability tracked as CVE-2026-74990, referenced by a Tenable/Nessus plugin as unpatched and affecting Linux distributions and related Firefox/Thunderbird/mozjs packages. The content does not describe the underlying flaw type, only that it is considered high severity by CVSS v3 metrics.
A critical vulnerability in Mozilla Thunderbird 140.14 referenced as the CVSS score source for this plugin; specific flaw details are not provided in the content.
A vulnerability affecting Mozilla Thunderbird and used as the CVSS score source in this Tenable plugin for macOS Thunderbird 140.14.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.