CVE-2026-31664

In the Linux kernel, the following vulnerability has been resolved: xfrm: clear trailing padding in build_polexpire() build_expire() clears the trailing padding bytes of struct xfrm_user_expire after setting the hard field via memset_after(), but the analogous function build_polexpire() does not do this for struct xfrm_user_polexpire. The padding bytes after the __u8 hard field are left uninitialized from the heap allocation, and are then sent to userspace via netlink multicast to XFRMNLGRP_EXPIRE listeners, leaking kernel heap memory contents. Add the missing memset_after() call, matching build_expire().

• linux linux kernel (>= 2.6.12.1 < 6.1.169) • linux linux kernel (>= 6.2 < 6.6.135) • linux linux kernel (>= 6.7 < 6.12.82) • linux linux kernel (>= 6.13 < 6.18.23) • linux linux kernel (>= 6.19 < 6.19.13) • linux linux kernel 2.6.12 • linux linux kernel 7.0