CVE-2026-98811: In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: reclaim an empty proto on the error path Two racing tc filter add requ

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: reclaim an empty proto on the error path Two racing tc filter add requ

In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_api: reclaim an empty proto on the error path Two racing tc filter add requests on the same chain/prio of an unlocked classifier both run change() on the shared proto and both can fail: the winner's tcf_chain_tp_delete_empty() attempt gives up because the loser's handle is still in the idr, and the loser's error path drops only its own reference without a second reclamation attempt. The empty proto stays linked in the chain, holding the chain reference, a block reference and the classifier module reference until the chain or block is torn down. Reclaim the proto on the error path of any failed request that holds a proto reference. The reclamation is emptiness-gated: tcf_chain_tp_delete_empty() unlinks the proto only when delete_empty() admits it is empty, so a live shared proto is never unlinked. A proto the request created is reclaimed unconditionally - it is the only owner, so marking it for deletion is safe even without a delete_empty callback. Classifiers without one (the check marks the proto unconditionally) are rtnl-serialized, so the raced window this guard closes cannot arise for them. T

Description from the National Vulnerability Database, published by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

What it means for a small business

Linux is on the computers, phones or browsers your team uses every day. Turn on automatic updates and restart: most of these fixes only take effect after a restart.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.17%, higher than 6% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

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Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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