CVE-2026-53212

Description

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.

References

• https://git.kernel.org/stable/c/349df61526d2e39decc685d246202e3e284cfe05
• https://git.kernel.org/stable/c/55b79b1ae42372012413ce0413181d26679b17ef
• https://git.kernel.org/stable/c/5e9ee18b27fde88cb6148202b33916c66693fe82
• https://git.kernel.org/stable/c/8767fe4079affa74314d7eb3220e700150289842
• https://git.kernel.org/stable/c/941d7394efda5e054e2d6f3e0dd0f6a9ba19aaa3