CVE-2026-43026

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> netfilter: ctnetlink: zero expect NAT fields when CTA_EXPECT_NAT absent<br /> <br /> ctnetlink_alloc_expect() allocates expectations from a non-zeroing<br /> slab cache via nf_ct_expect_alloc(). When CTA_EXPECT_NAT is not<br /> present in the netlink message, saved_addr and saved_proto are<br /> never initialized. Stale data from a previous slab occupant can<br /> then be dumped to userspace by ctnetlink_exp_dump_expect(), which<br /> checks these fields to decide whether to emit CTA_EXPECT_NAT.<br /> <br /> The safe sibling nf_ct_expect_init(), used by the packet path,<br /> explicitly zeroes these fields.<br /> <br /> Zero saved_addr, saved_proto and dir in the else branch, guarded<br /> by IS_ENABLED(CONFIG_NF_NAT) since these fields only exist when<br /> NAT is enabled.<br /> <br /> Confirmed by priming the expect slab with NAT-bearing expectations,<br /> freeing them, creating a new expectation without CTA_EXPECT_NAT,<br /> and observing that the ctnetlink dump emits a spurious<br /> CTA_EXPECT_NAT containing stale data from the prior allocation.