CVE-2026-80843

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

xfrm: fix xfrm_state_construct() auth-trunc leak

attach_auth_trunc() can allocate x->aalg while leaving

x->props.aalgo at zero when the selected auth algorithm has no

sadb_alg_id. One real case is cmac(aes).

xfrm_state_construct() then treats !x->props.aalgo as "no auth

algorithm attached yet" and calls attach_auth(). That overwrites

x->aalg and loses the first allocation. Any later failure or teardown

only frees the replacement pointer.

Check whether x->aalg is already attached instead of inferring that

state from x->props.aalgo.