CVE-2026-63911

Summary

In the Linux kernel, the following vulnerability has been resolved:

xfrm: iptfs: reset runtime state when cloning SAs

iptfs_clone_state() clones the IPTFS mode data with kmemdup(). This copies runtime objects which must not be shared with the original SA, including the embedded sk_buff_head, hrtimers, spinlock, and in-flight reassembly/reorder state.

If xfrm_state_migrate() fails after clone_state() but before the later init_state() call has reinitialized those fields, the cloned state can be destroyed by xfrm_state_gc_task() with list and timer state copied from the original SA. With queued packets this lets the clone splice and free skbs owned by the original IPTFS queue, leading to use-after-free and double-free reports in iptfs_destroy_state() and skb release paths.

Reinitialize the clone's runtime state before publishing it through x->mode_data. Because clone_state() now publishes a destroyable mode_data object before init_state(), take the mode callback module reference there. Avoid taking it again from __iptfs_init_state() for the same object.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/9327252e04626d4bb02ca8c0c108fbe8eabf0c5a
• https://git.kernel.org/stable/c/dfb9f6cbfa9826655a49698cf90eb800fce2178e
• https://git.kernel.org/stable/c/7f83d174073234839aea176f265e517e0d50a1d2

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