Use-after-free in Linux kernel - CVE-2026-98370

Vulnerability details

The vulnerability allows a local user to trigger a use-after-free in the kernel.

The vulnerability exists due to use-after-free in xfrm_alloc_userspi() and xfrm_user_rcv_msg() when processing compat ALLOCSPI requests. A local user can submit a compat ALLOCSPI request that causes a translated child buffer to be attached to the inbound request to trigger a use-after-free in the kernel.

Exploitation depends on a multicast clone sharing skb_shared_info with the request and a compat receiver still copying from the translated child when the request handler frees it.

Affected software

How to mitigate CVE-2026-98370

External References

• https://git.kernel.org/stable/c/17893987e52918c23945c42e47e894a936305a25
• https://git.kernel.org/stable/c/248433942155b42a0ef04a5806c8aca024ea7c33
• https://git.kernel.org/stable/c/2b63341e2ebc9b6f73cbd9214dbe7d46dd98c718
• https://git.kernel.org/stable/c/42971ea17c7a8afc0bdd5ca40648bf4e5bb7b810
• https://git.kernel.org/stable/c/494f2bee9d8d0ebcfa249ac41bed7fed26d119b4
• https://git.kernel.org/stable/c/bb63ab52a18273ec68340ac49aebbaa7b514ccd5
• https://git.kernel.org/stable/c/d1ebd9081879fd9ae9c8fb7e8928f19cc88ae320
• https://git.kernel.org/stable/c/e70f639aee2ff0def155c256cace9e0f81d998e2

Related Security Bulletins

• Use-after-free in Linux kernel xfrm
• Debian update for linux