SB20261022183 - Race condition in Linux kernel net ovpn driver

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-98603)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 2 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local user to disrupt VPN packet routing, potentially causing a denial of service.

The vulnerability exists due to a race condition in the Linux kernel ovpn UDP output functions when clearing a remembered local source address that is no longer usable during concurrent transmissions. A local user can trigger concurrent use of the affected output path to cause lockless IPv6 readers to observe a partially updated source address, potentially disrupting VPN traffic.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/72bd1bea37ea2c8553938f086bf48ccd2147dfe1
• https://git.kernel.org/stable/c/7d8104988f423572df1f3347ce578037b1043f34
• https://git.kernel.org/stable/c/c44a04722f7dae9a45a101b8e100931ab59f1c18