Input validation error in OpenVPN Server - CVE-2026-35058

CSH
CYBERSECURITY HELP
Sign In REGISTER
 
Main Vulnerability Database Vulnerabilities #VU127529

Input validation error in OpenVPN Server - CVE-2026-35058

Published: April 24, 2026


Vulnerability identifier: #VU127529
CSH Severity: Low
CVSS v4: 6 [CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-35058
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability: No public exploit available

Vulnerability details

The vulnerability allows a remote user to cause a denial of service.

The vulnerability exists due to improper input validation in tls_crypt_v2_extract_client_key and tls_crypt_unwrap when processing a malformed control channel packet. A remote user can send a specially crafted packet to cause a denial of service.

Only setups using tls-crypt-v2 are vulnerable. Exploitation requires possession of a valid tls-crypt-v2 client key, or observation of a handshake using a key with a specific byte property, or injection into a live client session.


Affected software

OpenVPN Server
Debian Linux
Fedora
openEuler
Ubuntu
openvpn-debuginfo
openvpn
openvpn-debugsource
openvpn-devel
openvpn-help
openvpn (Ubuntu package)
openvpn (Debian package)

How to mitigate CVE-2026-35058

Install security update from vendor's website.

OpenVPN Server - addressed in versions 2.6.20, 2.7.2
openvpn-debuginfo - addressed in versions 2.5.5-7, 2.6.9-7
openvpn - addressed in versions 2.5.5-7, 2.6.9-7
openvpn-debugsource - addressed in versions 2.5.5-7, 2.6.9-7
openvpn-devel - addressed in versions 2.5.5-7, 2.6.9-7
openvpn-help - addressed in versions 2.5.5-7, 2.6.9-7
openvpn (Ubuntu package) - addressed in versions 2.5.11-0ubuntu0.22.04.3, 2.6.19-0ubuntu0.24.04.2, 2.6.19-0ubuntu0.25.10.2, 2.7.0-1ubuntu1.1
openvpn (Debian package) - addressed in versions 2.6.14-0+deb12u1, 2.6.14-1+deb13u2
openvpn - addressed in versions 2.6.20-1.fc42, 2.6.20-1.fc43, 2.7.2-1.el10_1, 2.7.2-1.el10_2, 2.7.2-1.el10_3, 2.7.2-1.fc44, 2.7.3-1.el10_1, 2.7.3-1.el10_2, 2.7.3-1.el10_3, 2.7.3-1.fc44

External References

Related Security Bulletins