Bug 2492839 (CVE-2026-53160)

Summary: CVE-2026-53160 kernel: misc: fastrpc: fix use-after-free race in fastrpc_map_create
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's fastrpc component. A race condition in the `fastrpc_map_create` function allows for a use-after-free vulnerability. This could enable an attacker to cause system instability, disclose sensitive information, or potentially execute unauthorized code.
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Description OSIDB Bzimport 2026-06-25 10:08:26 UTC 
In the Linux kernel, the following vulnerability has been resolved:

misc: fastrpc: fix use-after-free race in fastrpc_map_create

fastrpc_map_lookup returns a raw pointer after releasing fl->lock. The
caller fastrpc_map_create then calls fastrpc_map_get (kref_get_unless_zero)
on this unprotected pointer. A concurrent MEM_UNMAP can free the map
between the lock release and the kref operation, resulting in a
use-after-free on the freed slab object.

Restore the take_ref parameter to fastrpc_map_lookup so the reference
is acquired atomically under fl->lock before the pointer is exposed to
the caller.
Comment 1 Keith Grant 2026-06-26 01:25:49 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062549-CVE-2026-53160-1531@gregkh/T