SB20260427174 - Fedora 44 update for openvpn



SB20260427174 - Fedora 44 update for openvpn

Published: April 27, 2026

Security Bulletin ID SB20260427174
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 vulnerabilities.


1) Race condition (CVE-ID: CVE-2026-40215)

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

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear


The vulnerability allows a remote attacker to disclose packet data from a previous handshake.

The vulnerability exists due to a race condition in the TLS handshake handling when processing reconnecting sessions. A remote attacker can trigger repeated handshake activity to disclose packet data from a previous handshake.

This occurs only under specific circumstances involving replacement of an old TLS session by a new session while stale session state still attempts to send a packet.


2) Input validation error (CVE-ID: CVE-2026-35058)

CWE-ID: CWE-20 - Improper input validation

CVSSv4: 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/E:U/U:Clear


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.


Remediation

Install update from vendor's website.