Bug 2506805 (CVE-2026-64217)

Summary: CVE-2026-64217 kernel: Linux kernel netfs: Memory corruption leading to denial of service and potential privilege escalation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerability-draftAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's netfs component. A local user can exploit this vulnerability by performing specific file I/O operations on a netfs-backed mount, leading to an overrun in the `netfs_extract_user_iter()` function. This memory corruption can cause a kernel crash, resulting in a Denial of Service (DoS). In some cases, it may also lead to privilege escalation by allowing unauthorized access to sensitive kernel memory.
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Description OSIDB Bzimport 2026-07-24 16:04:25 UTC 
In the Linux kernel, the following vulnerability has been resolved:

netfs: Fix overrun check in netfs_extract_user_iter()

Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills
pages[], then those pages don't get included in the iterator constructed at
the end of the function.  If there was an overfill, memory corruption has
already happened.
Comment 1 Mauro Matteo Cascella 2026-07-28 11:06:26 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026072415-CVE-2026-64217-889e@gregkh/T