Bug 2492847 (CVE-2026-53212) - CVE-2026-53212 kernel: netfilter: nft_tunnel: fix use-after-free on object destroy
Summary: CVE-2026-53212 kernel: netfilter: nft_tunnel: fix use-after-free on object de...
Keywords:
Status: NEW
Alias: CVE-2026-53212
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-25 10:08 UTC by OSIDB Bzimport
Modified: 2026-06-25 16:39 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
Environment:
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Description OSIDB Bzimport 2026-06-25 10:08:50 UTC
In the Linux kernel, the following vulnerability has been resolved:

netfilter: nft_tunnel: fix use-after-free on object destroy

nft_tunnel_obj_destroy() calls metadata_dst_free() which directly
kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets
that took a reference via dst_hold() in nft_tunnel_obj_eval() and
are still queued (e.g. in a netem qdisc) are left with a dangling
pointer. When these packets are eventually dequeued, dst_release()
operates on freed memory.

Replace metadata_dst_free() with dst_release() so the metadata_dst
is freed only after all references are dropped. The dst subsystem
already handles metadata_dst cleanup in dst_destroy() when
DST_METADATA is set.

Comment 1 Mauro Matteo Cascella 2026-06-25 16:37:46 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062503-CVE-2026-53212-ce23@gregkh/T


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