Executive brief
OpenVPN is a widely used software for creating secure private network connections. A vulnerability in how it handles specific encrypted packets allows an authorized user to crash the VPN server. This results in a denial of service, preventing other users from connecting or maintaining their secure sessions until the service is restarted.
Technical details
A reachable assertion vulnerability (CWE-617) exists in OpenVPN's tls-crypt-v2 key extraction logic. The software fails to properly validate packet lengths before processing, which can be triggered by an authenticated attacker sending a specially crafted packet. This results in a fatal assertion that crashes the OpenVPN process, leading to a denial of service. The vulnerability affects versions 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1, and has been addressed in versions 2.6.20 and 2.7.2.
Affected products
- OpenVPN Inc. OpenVPN 2.6.0 through 2.6.19, 2.7_alpha1 through 2.7.1
Timeline
- 2026-04-22: patched: Fixed in OpenVPN 2.6.20 and 2.7.2
- 2026-06-08: disclosed: NVD publication date