CVE-2026-68162

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

sctp: avoid auth_enable sysctl UAF during netns teardown

proc_sctp_do_auth() updates the SCTP control socket after changing net.sctp.auth_enable. The handler gets the per-net SCTP state from ctl->data, so an already opened sysctl file can still target a network namespace while that namespace is being torn down.

SCTP previously registered its per-net sysctls from sctp_defaults_init(), while the control socket is created later from sctp_ctrlsock_init(). This exposed a window during initialization where auth_enable was writable before net->sctp.ctl_sock existed, and a teardown window where auth_enable stayed writable after inet_ctl_sock_destroy() had released the control socket.

Move the per-net SCTP sysctl registration into sctp_ctrlsock_init() after sctp_ctl_sock_init() succeeds, and unregister the sysctl table before destroying the control socket in sctp_ctrlsock_exit(). If sysctl registration fails after the control socket was created, destroy the control socket in the same init path.

Make sctp_sysctl_net_unregister() tolerate a missing header and clear the saved pointer so init-error and exit paths can safely share the unregister helper.

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 Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.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/158f3cc332dc53f43ec20060233d7c3cecd6d912
• https://git.kernel.org/stable/c/19573dcddb8819fd68d6cd1f916c1c99c3fa4ff4
• https://git.kernel.org/stable/c/626bda8cfe43dff19a9833ff6ba055a817b5455c
• https://git.kernel.org/stable/c/66700c0719675e0e118ae83b2d7168dacd69dd3d
• https://git.kernel.org/stable/c/a50e73488e0bbdd262b3be3c9a1d8dd078382381
• https://git.kernel.org/stable/c/be6aae9d1b91c603adb35872d37d40e83daf8758
• https://git.kernel.org/stable/c/ceb7190b5c873d4a1267a1600c5aa52c600e929f
• https://git.kernel.org/stable/c/f8d5e7846025f4ab15a461235f8ebae9094a361a
• https://git.kernel.org/stable/c/fd66854a22661929245f3d2b244c432bc8b1a150