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CVE-2025-40040 is an incorrect numeric-type conversion in the Linux kernel's KSM ksm_madvise() logic. On 64-bit builds, applying MADV_UNMERGEABLE to a virtual memory area registered for userfaultfd MINOR mode can complement a 32-bit VM_MERGEABLE constant and zero-extend the resulting mask during an operation on the 64-bit vm_flags field. The operation clears the upper 32 bits of vm_flags rather than only VM_MERGEABLE. This can remove userfaultfd flags while leaving a valid vm_userfaultfd_ctx pointer, producing inconsistent userfaultfd VMA state during userfaultfd_release_all().
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No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
All candidate exploits were filtered out by Mallory's validation.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
21 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
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.