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CVE-2026-43026 In the Linux kernel, the following vulnerability has been resolved: netfilter: ctnetlink: zero expect NAT fields when…

Description

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.

Affected products and versions

Product Affected versions Fixed in
Linux 7.0 earliest → < 7.0 7.0
Linux 6.19 earliest → < 6.19.12 6.19.12
Linux 6.18 earliest → < 6.18.22 6.18.22
Linux 6.12 earliest → < 6.12.81 6.12.81
Linux 6.6 earliest → < 6.6.134 6.6.134
Linux 6.1 earliest → < 6.1.168 6.1.168
Linux 5.15 earliest → < 5.15.203 5.15.203
Linux 5.10 earliest → < 5.10.253 5.10.253
Linux 3.4 No fix stated
Show the 3 other branches
Product Affected versions Fixed in
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated

References

Timeline

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