# CVE-2026-72326: net/sched: cake: reject overhead values that underflow length

> An integer underflow in the Linux kernel CAKE scheduler allows remote attackers to cause denial of service via crafted network packets.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 15 Aug 2026
- **Updated:** 17 Aug 2026
- **Also known as:** BELL-CVE-2026-72326, DEBIAN-CVE-2026-72326, GHSA-mqfm-gm6r-72rv, UBUNTU-CVE-2026-72326

## What is CVE-2026-72326?

CVE-2026-72326 is a vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

net/sched: cake: reject overhead values that underflow length

CAKE accepts signed overhead values and stores them in an s16, but the
adjusted packet length calculation uses unsigned arithmetic.  A negative
effective length can therefore wrap to a large value.

Such configurations make rate accounting depend on integer wraparound
rather than on the packet size userspace intended to model.  A static
netlink lower bound is not enough because packets reaching CAKE can be
smaller than any reasonable manual-overhead allowance.

Fold the signed overhead adjustment into the existing datapath MPU clamp
so negative adjusted lengths are clamped before link-layer framing
adjustments.

## Which versions are affected by CVE-2026-72326?


## How do I fix CVE-2026-72326?

Apply the vendor's patch.

## Is CVE-2026-72326 being exploited?

There is no known exploitation of CVE-2026-72326 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72326 and fix it if it is affected.

What it is: CVE-2026-72326 is a vulnerability in Linux, published on 15 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-72326 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-2026-72326/ (Markdown: https://insights.sbomify.com/CVE-2026-72326/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72326
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72326
- OSV: https://osv.dev/vulnerability/CVE-2026-72326

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72326/
Summaries are generated and may contain mistakes; the official description above is the record.