Bug 2516873 (CVE-2026-74379)

Summary: CVE-2026-74379 kernel: dax/kmem: account for partial discontiguous resource upon removal
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: low    
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 `dax/kmem` module. This vulnerability occurs when the system attempts to remove a memory resource that was not fully initialized, leading to an attempt to access a null pointer. A local attacker could potentially trigger this condition, causing the system to crash and resulting in a Denial of Service (DoS).
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Description OSIDB Bzimport 2026-08-15 06:37:58 UTC 
In the Linux kernel, the following vulnerability has been resolved:

dax/kmem: account for partial discontiguous resource upon removal

When dev_dax_kmem_probe() partially succeeds (at least one range is
mapped) but a subsequent range fails request_mem_region() or
add_memory_driver_managed(), the probe silently continues, ultimately
returning success, but with the corresponding range resource NULL'ed out.

dev_dax_kmem_remove() iterates over all dax_device ranges regardless of if
the underlying resource exists.  When remove_memory() is called later, it
returns 0 because the memory was never added which causes
dev_dax_kmem_remove() to incorrectly assume the (nonexistent) resource can
be removed and attempts cleanup on a NULL pointer.

Fix this by skipping these ranges altogether, noting that these cases are
considered success, such that the cleanup is still reached when all
actually-added ranges are successfully removed.
Comment 1 Keith Grant 2026-08-20 19:44:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026081504-CVE-2026-74379-afe7@gregkh/T