CVE-2026-97959

/// Technical description

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

net/sched: cls_route: free emptied bucket on filter move

route4_change can move an existing filter to a different top-level

bucket: route4_set_parms recomputes the handle from TCA_ROUTE4_TO/

FROM/IIF, and the handle-mismatch check is gated on the 'new' flag, so

for an existing filter the new handle may differ from the old one and

land in a different bucket. When this happens, the filter is unlinked

from the old bucket, but the bucket itself is never freed once it goes

empty. The stale empty bucket remains in head->table[], causing

route4_delete to report *last=false even after the last live filter is

gone. That pins the empty tcf_proto and causes a leak.

Fix this by refcounting the filters linked to a bucket and freeing the

bucket when the count drops to zero. The existing scan in route4_delete

goes away with it.

The count is updated at all sites that link or unlink a filter during add,

change and delete, and the b

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References