CVE-2026-74946 is a privilege escalation vulnerability in Mozilla's Graphics: CanvasWebGL component caused by incorrect boundary conditions. The flaw affects Firefox and Thunderbird and was addressed in Firefox 154, Firefox ESR 115.39, Firefox ESR 140.14, Firefox ESR 153.1, Thunderbird 154, Thunderbird 140.14, and Thunderbird 153.1. The available information identifies the vulnerable area as CanvasWebGL boundary handling, but does not provide function-level details or a deeper root-cause analysis beyond the boundary-condition error.
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What an attacker gets, and what they’ve been doing with it.
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Patch, then assume compromise.
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.
12 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 vulnerability tracked as CVE-2026-74946 affecting Linux distributions and related Mozilla package builds such as Firefox and Thunderbird packages, as referenced by the listed CPEs. The content does not describe the underlying flaw type.
Unknown; listed as one of multiple vulnerabilities addressed by Mozilla Thunderbird 140.14.
A vulnerability affecting Mozilla Thunderbird, referenced by a 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.