UBUNTU-CVE-2026-80843

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UBUNTU-CVE-2026-80843

Summary:

Details: 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.

References: https://ubuntu.com/security/CVE-2026-80843, https://www.cve.org/CVERecord?id=CVE-2026-80843, https://git.kernel.org/linus/c12cbf56320fb633484ee0ca1fb7d68d6b64b213