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

net: shaper: protect from late creation of hierarchy

We look up a netdev during prep of Netlink ops (pre- callbacks)
and take a ref to it. Then later in the body of the callback
we take its lock or RCU which are the actual protections.

The netdev may get unregistered in between the time we take
the ref and the time we lock it. We may allocate the hierarchy
after flush has already run, which would lead to a leak.

Take the instance lock in pre- already, this saves us from the race
and removes the need for dedicated lock/unlock callbacks completely.
After all, if there's any chance of write happening concurrently
with the flush - we're back to leaking the hierarchy.

We may take the lock for devices which don't support shapers but
we're only dealing with SET operations here, not taking the lock
would be optimizing for an error case.

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History

Fri, 03 Apr 2026 21:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362
CWE-399

Fri, 03 Apr 2026 16:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: net: shaper: protect from late creation of hierarchy We look up a netdev during prep of Netlink ops (pre- callbacks) and take a ref to it. Then later in the body of the callback we take its lock or RCU which are the actual protections. The netdev may get unregistered in between the time we take the ref and the time we lock it. We may allocate the hierarchy after flush has already run, which would lead to a leak. Take the instance lock in pre- already, this saves us from the race and removes the need for dedicated lock/unlock callbacks completely. After all, if there's any chance of write happening concurrently with the flush - we're back to leaking the hierarchy. We may take the lock for devices which don't support shapers but we're only dealing with SET operations here, not taking the lock would be optimizing for an error case.
Title net: shaper: protect from late creation of hierarchy
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-04-03T15:15:21.280Z

Reserved: 2026-01-13T15:37:46.017Z

Link: CVE-2026-23436

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-04-03T16:16:25.257

Modified: 2026-04-03T16:16:25.257

Link: CVE-2026-23436

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-04-03T21:16:15Z

Weaknesses