CVE-2026-43026
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.
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
No mitigations published for this CVE yet.
The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.
✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here withsource_tier=community-verified.
OS impact
| OS | Version | Status | Fixed in |
|---|---|---|---|
| sles | affected | | |
| debian | bookworm | fixed | 6.1.170-1 |
| debian | forky | fixed | 6.19.12-1 |
| debian | sid | fixed | 6.19.12-1 |
| debian | trixie | fixed | 6.12.85-1 |
| debian | bullseye | fixed | 6.1.170-1~deb11u1 |
| linux-kernel | affected | 5.10.253 | |
| linux-kernel | 7.0 | affected | |
Application impact
| Vendor | Product | Versions | Fixed |
|---|---|---|---|
| gcp | | |
References
- https://git.kernel.org/stable/c/1c2ebdeff8d088a2e47ae25d7b38447249adace2
- https://git.kernel.org/stable/c/2898080c054ea4d6ddfaaf21bbedbc229a9a8376
- https://git.kernel.org/stable/c/35177c6877134a21315f37d57a5577846225623e
- https://git.kernel.org/stable/c/929f7a9a7aad9404a5867216c3f8738232355b38
- https://git.kernel.org/stable/c/a5a89db6981a1ddf2314bf50cb49db5a3146185f
- https://git.kernel.org/stable/c/a64b7bf84b4d5ea54218c5d374ec87fff9000f43
- https://git.kernel.org/stable/c/bff0f4f06f12d6d9bc565a3e1378abd4f6f5ce36
- https://git.kernel.org/stable/c/fd002ff2ea030cbfb0188a11b3c60ce7f84485f4
- https://www.suse.com/security/cve/CVE-2026-43026.html
- https://security-tracker.debian.org/tracker/CVE-2026-43026
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.