CVEvulnerability
CVE-2026-72430
- Status
- Received
- Published
- 2026-08-15
- Last modified
- 2026-08-17
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Description
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.
References
- https://git.kernel.org/stable/c/0c3d8fc87e10e38fe054ece009d6d1f66bef2cd4 git.kernel.org
- https://git.kernel.org/stable/c/13b561c893c741635adce3781490a7a1099106c8 git.kernel.org
- https://git.kernel.org/stable/c/16e088016f38cf728a0de709c3335cc5a3850476 git.kernel.org
- https://git.kernel.org/stable/c/1d51aff78f078af1a80e9496c2f4643f4c0ef0a0 git.kernel.org