Bug 2482029 (CVE-2026-46042) - CVE-2026-46042 kernel: mm/mempolicy: fix memory leaks in weighted_interleave_auto_store()
Summary: CVE-2026-46042 kernel: mm/mempolicy: fix memory leaks in weighted_interleave_...
Keywords:
Status: NEW
Alias: CVE-2026-46042
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:07 UTC by OSIDB Bzimport
Modified: 2026-05-27 19:41 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-05-27 15:07:50 UTC
In the Linux kernel, the following vulnerability has been resolved:

mm/mempolicy: fix memory leaks in weighted_interleave_auto_store()

weighted_interleave_auto_store() fetches old_wi_state inside the if
(!input) block only.  This causes two memory leaks:

1. When a user writes "false" and the current mode is already manual,
   the function returns early without freeing the freshly allocated
   new_wi_state.

2. When a user writes "true", old_wi_state stays NULL because the
   fetch is skipped entirely. The old state is then overwritten by
   rcu_assign_pointer() but never freed, since the cleanup path is
   gated on old_wi_state being non-NULL. A user can trigger this
   repeatedly by writing "1" in a loop.

Fix both leaks by moving the old_wi_state fetch before the input check,
making it unconditional.  This also allows a unified early return for both
"true" and "false" when the requested mode matches the current mode.

Reviewed by: Donet Tom <donettom.com>


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