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CVE-2026-42831 is a critical heap-based buffer overflow vulnerability in Microsoft Office, including reporting that specifically identifies Office for Android as affected. The flaw is triggered when a victim opens a specially crafted malicious Office document. Microsoft describes the issue as allowing an unauthorized attacker to execute code locally; however, the attack scenario is document-based and attacker-driven, so the practical outcome is remote code execution on the victim device once the file is opened. Microsoft notes that the Preview Pane is not an attack vector. The available information does not identify the specific vulnerable function or parser component beyond the heap-based overflow condition.
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What an attacker gets, and what they’ve been doing with it.
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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.
4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A Microsoft Office/Word vulnerability exploitable through crafted documents.
An Office/Word vulnerability exploitable via crafted documents.
A critical heap-based buffer overflow vulnerability in Office for Android that allows local code execution when a user opens a malicious Office file.
A critical heap-based buffer overflow remote code execution vulnerability in Microsoft Office that requires user interaction to open a malicious Office file; despite the RCE title, exploitation occurs locally on the victim machine.
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.