SB2026103083 - Ubuntu update for openvpn

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Main Vulnerability Database SB2026103083

SB2026103083 - Ubuntu update for openvpn

Published: October 30, 2026

Security Bulletin ID SB2026103083
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Data manipulation

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Improper Neutralization of Null Byte or NUL Character (CVE-ID: CVE-2026-84790)

CWE-ID: CWE-158 - Improper Neutralization of Null Byte or NUL Character

CVSSv4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]


The vulnerability allows a remote attacker to potentially bypass intended certificate subject validation.

The vulnerability exists due to improper handling of null bytes in OpenVPN certificate subject validation when processing certificates containing embedded null bytes. A remote attacker can present a specially crafted certificate subject to potentially cause inconsistent interpretation of its contents and bypass intended certificate subject checks.

mbedTLS builds already reject certificates containing null bytes.


Remediation

Install update from vendor's website.

References