What’s Vulnerable › Vulnerabilities

CVE-2025-68191: udp_tunnel: use netdev_warn() instead of netdev_WARN()

• Severity: unknown
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-12-16 · updated 2026-10-14

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.

Affected products

• Linux kernel: 5.9 — fixed in 6.18

How to fix

Upgrade to a fixed version: Linux kernel 6.18. Check the vendor advisory for mitigations.

References

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

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