CVE-2026-43026

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

netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent

ctnetlink_alloc_expect() allocates expectations from a non-zeroing

slab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not

present in the netlink message, saved_addr and saved_proto are

never initialized. Stale data from a previous slab occupant can

then be dumped to userspace by ctnetlink_exp_dump_expect(), which

checks these fields to decide whether to emit CTA_EXPECT_NAT.

The safe sibling nf_ct_expect_init(), used by the packet path,

explicitly zeroes these fields.

Zero saved_addr, saved_proto and dir in the else branch, guarded

by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when

NAT is enabled.

Confirmed by priming the expect slab with NAT-bearing expectations,

freeing them, creating a new expectation without CTA_EXPECT_NAT,

and observing that the ctnetlink dump emits a spurious

CTA_EXPECT_NAT containing stale data from the prior allocation.