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

> A local attacker with high privileges can cause a denial of service by creating a network packet mirroring loop that bypasses loop detection.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Jul 2026
- **Updated:** 19 Jul 2026
- **Also known as:** DEBIAN-CVE-2026-63982, GHSA-g6rc-cvjj-cfmj, UBUNTU-CVE-2026-63982

## What is CVE-2026-63982?

CVE-2026-63982 is a denial of service vulnerability in Linux, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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 sched_mirred_dev array dev is lost because of 1) the packet
deferral into the backlog and 2) the fact the sched_mirred_dev 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

## Which versions are affected by CVE-2026-63982?


## How do I fix CVE-2026-63982?

Apply the vendor's patch.

## Is CVE-2026-63982 being exploited?

There is no known exploitation of CVE-2026-63982 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63982 and fix it if it is affected.

What it is: CVE-2026-63982 is a denial of service vulnerability in Linux, published on 19 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-63982 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63982/ (Markdown: https://insights.sbomify.com/CVE-2026-63982/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63982
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63982
- OSV: https://osv.dev/vulnerability/CVE-2026-63982

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63982/
Summaries are generated and may contain mistakes; the official description above is the record.