CVE-2026-72430

Summary

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

net/sched: act_ct: fix nf_connlabels leak on two error paths

tcf_ct_fill_params() calls nf_connlabels_get() (setting put_labels) when TCA_CT_LABELS is present, but two later error sites use a bare return instead of "goto err", skipping the err: nf_connlabels_put() cleanup. They also precede the "p->put_labels = put_labels" assignment, so the tcf_ct_params_free() fallback does not release the count either. Each failed RTM_NEWACTION on these paths leaks one nf_connlabels reference: net->ct.labels_used is incremented and never released. The action is reachable with CAP_NET_ADMIN over the netns, i.e. from an unprivileged user namespace on default-userns kernels.

Impact: an unprivileged user with CAP_NET_ADMIN over a network namespace (e.g. via user namespaces) leaks one nf_connlabels reference per failed RTM_NEWACTION on the two error paths; net->ct.labels_used is never released.

The err: label is safe to reach from both sites: p->tmpl is still NULL there (kzalloc'd, not yet assigned) and nf_ct_put(NULL) is a no-op, so no inline release is needed.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/13b561c893c741635adce3781490a7a1099106c8
• https://git.kernel.org/stable/c/1d51aff78f078af1a80e9496c2f4643f4c0ef0a0
• https://git.kernel.org/stable/c/0c3d8fc87e10e38fe054ece009d6d1f66bef2cd4
• https://git.kernel.org/stable/c/16e088016f38cf728a0de709c3335cc5a3850476

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