CVE-2026-63919

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

xfrm: input: hold netns during deferred transport reinjection

Transport-mode reinjection stores a struct net pointer in skb->cb and uses it later from xfrm_trans_reinject(). That pointer must stay valid until the deferred callback runs.

Take a netns reference when queueing deferred reinjection work and drop it after the callback completes. Use maybe_get_net() so the queueing path does not revive a namespace that is already being torn down.

This keeps the existing workqueue design and fixes the netns lifetime handling in one place for all users of xfrm_trans_queue_net().

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/2df7059a18afb7d3aee6c36cad5d371c198111d4
• https://git.kernel.org/stable/c/48ce101cd630d6745b6923b5bad8358bc4c119da
• https://git.kernel.org/stable/c/55ddfc41451f01c588089cd74957a05311b6f202
• https://git.kernel.org/stable/c/7ee59eda8820b758ed29e1cd3222359c7b97302c
• https://git.kernel.org/stable/c/8dfabcba6a943a7a02ebe1e1637c361ba96acbaa
• https://git.kernel.org/stable/c/9f67a36e91bb50d358760f381f233913fe5c09f8
• https://git.kernel.org/stable/c/9f7ebb45a83afc3216e855e57d51bb4bc9b5232e
• https://git.kernel.org/stable/c/c16f74dc1d75d0e2e7670076d5375deda110ebeb