CVE-2026-63982: net/sched: Fix ethx:ingress -> ethy:egress -> ethx:ingress mirred loop

Published Jul 19, 2026

Updated

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

net/sched: Fix ethx:ingress -> ethy:egress -> ethx:ingress mirred loop

When mirred redirects to ingress (from either ingress or egress) the loop state from schedmirreddev array dev is lost because of 1) the packet deferral into the backlog and 2) the fact the schedmirreddev array is cleared. In such cases, if there was a loop we won't discover it.

Here's a simple test to reproduce: ip a add dev port0 10.10.10.11/24

tc qdisc add dev port0 clsact tc filter add dev port0 egress protocol ip \ prio 10 matchall action mirred ingress redirect dev port1

tc qdisc add dev port1 clsact tc filter add dev port1 ingress protocol ip \ prio 10 matchall action mirred egress redirect dev port0

ping -c 1 -W0.01 10.10.10.10

Affected Software

1 affected component

Linux Kernel

Event History

Jul 19, 2026

CVE Published

via MITRE·02:56 PM

Data Sourced

via MITRE·02:56 PM

Description

Data Sourced

via NVD·04:17 PM

Description

Frequently Asked Questions

What configuration is required for this loop to occur?

The reproduced condition uses TC clsact qdiscs and mirred redirect actions that send traffic from one interface's egress to another interface's ingress, then redirect it back to the first interface's egress. The affected path specifically involves redirects to ingress.

Is this triggered by ordinary network traffic alone?

No. The provided reproduction requires TC filters and mirred redirect rules to be configured on the involved interfaces. A packet such as the shown ping then traverses the configured redirect loop.

What can be done while a fixed kernel is unavailable?

Avoid TC mirred configurations that redirect packets to ingress in a path that can return traffic to the originating interface. Review paired ingress and egress redirect rules for cycles between interfaces.

CVE-2026-63982: net/sched: Fix ethx:ingress -> ethy:egress -> ethx:ingress mirred loop

Affected Software

Event History

Frequently Asked Questions

What configuration is required for this loop to occur?

Is this triggered by ordinary network traffic alone?

What can be done while a fixed kernel is unavailable?

Company

Resources

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Frequently Asked Questions

What configuration is required for this loop to occur?

Is this triggered by ordinary network traffic alone?

What can be done while a fixed kernel is unavailable?