CVE-2026-98235: net/sched: act_api: release tail references on DELACTION failure
In the Linux kernel, the following vulnerability has been resolved:
net/sched: actapi: release tail references on DELACTION failure
A batched RTMDELACTION request takes a temporary reference on each action before attempting any deletion. tcfactiondelete() clears each processed slot and drops its temporary reference before attempting the deletion. If deletion fails, tcaactiongd() calls tcfactionputmany() to release the remaining references, but its tcfactforeachaction() iterator stops at the first NULL slot.
When a batch stops at an action bound to a filter, this leaks a reference on each subsequent action. A later delete of an unbound action can then return success without removing it from the IDR.
Walk the full array in tcfactionputmany() and skip NULL slots to release the references held on the unprocessed actions.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
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debian/linuxto a version that resolves this vulnerability.Fixed in 6.1.176-1Fixed in 6.1.190-1Fixed in 6.12.115-2Fixed in 7.2.12-1Fixed in 7.2.15-1 - Upgrade
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debian/linux-6.12to a version that resolves this vulnerability.Fixed in 6.12.113-1~deb12u1 - Upgrade
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ubuntu/linux-hwe-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42~24.04.1 - Upgrade
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ubuntu/linux-riscv-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1~24.04.1 - Upgrade
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ubuntu/linuxto a version that resolves this vulnerability.Fixed in 7.0.0-42.42 - Upgrade
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ubuntu/linux-awsto a version that resolves this vulnerability.Fixed in 7.0.0-1016.17 - Upgrade
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ubuntu/linux-gcpto a version that resolves this vulnerability.Fixed in 7.0.0-1016.18 - Upgrade
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ubuntu/linux-ibmto a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oem-7.0to a version that resolves this vulnerability.Fixed in 7.0.0-1017.17 - Upgrade
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ubuntu/linux-oracleto a version that resolves this vulnerability.Fixed in 7.0.0-1015.16 - Upgrade
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ubuntu/linux-riscvto a version that resolves this vulnerability.Fixed in 7.0.0-42.42.1
Event History
Frequently Asked Questions
What conditions are needed to trigger the issue?
The issue requires a batched RTM_DELACTION request in which deletion fails at an action that is bound to a filter. Actions later in that batch can retain temporary references because earlier processed slots are NULL.
What is the observable impact after a failed batch deletion?
Subsequent actions in the batch may leak references. A later deletion of an unbound action can report success while failing to remove that action from the IDR.
How can administrators identify a potentially affected system?
A potentially affected system has experienced a failed batched RTM_DELACTION request that stopped at an action bound to a filter, followed by deletion operations that report success but leave an unbound action present in the IDR.