Bug 2492778 (CVE-2026-53247) - CVE-2026-53247 kernel: net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
Summary: CVE-2026-53247 kernel: net: ethernet: mtk_eth_soc: Fix use-after-free in meta...
Keywords:
Status: NEW
Alias: CVE-2026-53247
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
unspecified
unspecified
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-25 10:05 UTC by OSIDB Bzimport
Modified: 2026-06-26 00:10 UTC (History)
2 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-06-25 10:05:16 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown

mtk_free_dev() calls metadata_dst_free() which frees the metadata_dst
with kfree() immediately, bypassing the RCU grace period.
In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from
the skb to the metadata_dst. This function requires RCU read-side
protection and the dst must remain valid until all RCU readers complete.
Since metadata_dst_free() calls kfree() directly, a use-after-free can
occur if any skb still holds a noref pointer to the dst when the driver
tears it down.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path: when the refcount drops to zero, it schedules
the actual free via call_rcu_hurry(), ensuring all RCU readers have
completed before the memory is freed.


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