Vulnerability Database

383,426

Total vulnerabilities in the database

CVE-2005-3409 — openvpn / openvpn

OpenVPN 2.x before 2.0.4, when running in TCP mode, allows remote attackers to cause a denial of service (segmentation fault) by forcing the accept function call to return an error status, which leads to a null dereference in an exception handler.

  • Published: Nov 2, 2005
  • Updated: Sep 13, 2026
  • CVE: CVE-2005-3409
  • Severity: Medium
  • Exploit:
  • CISA KEV:

CVSS v2:

  • Severity: Medium
  • Score: 5
  • AV:N/AC:L/Au:N/C:N/I:N/A:P

No CWE or OWASP classifications available.

Software Affected versions
openvpn / openvpn = 2.0
openvpn / openvpn = 2.0.1_rc1
openvpn / openvpn = 2.0.1_rc2
openvpn / openvpn = 2.0.1_rc3
openvpn / openvpn = 2.0.1_rc4
openvpn / openvpn = 2.0.1_rc5
openvpn / openvpn = 2.0.1_rc6
openvpn / openvpn = 2.0.1_rc7
openvpn / openvpn = 2.0.2_rc1
openvpn / openvpn = 2.0.3_rc1
openvpn / openvpn = 2.0_beta1
openvpn / openvpn = 2.0_beta2
openvpn / openvpn = 2.0_beta3
openvpn / openvpn = 2.0_beta4
openvpn / openvpn = 2.0_beta5
openvpn / openvpn = 2.0_beta6
openvpn / openvpn = 2.0_beta7
openvpn / openvpn = 2.0_beta8
openvpn / openvpn = 2.0_beta9
openvpn / openvpn = 2.0_beta10
openvpn / openvpn = 2.0_beta11
openvpn / openvpn = 2.0_beta12
openvpn / openvpn = 2.0_beta13
openvpn / openvpn = 2.0_beta15
openvpn / openvpn = 2.0_beta16
openvpn / openvpn = 2.0_beta17
openvpn / openvpn = 2.0_beta18
openvpn / openvpn = 2.0_beta19
openvpn / openvpn = 2.0_beta20
openvpn / openvpn = 2.0_beta28
openvpn / openvpn = 2.0_rc1
openvpn / openvpn = 2.0_rc2
openvpn / openvpn = 2.0_rc3
openvpn / openvpn = 2.0_rc4
openvpn / openvpn = 2.0_rc5
openvpn / openvpn = 2.0_rc6
openvpn / openvpn = 2.0_rc7
openvpn / openvpn = 2.0_rc8
openvpn / openvpn = 2.0_rc9
openvpn / openvpn = 2.0_rc10
openvpn / openvpn = 2.0_rc11
openvpn / openvpn = 2.0_rc12
openvpn / openvpn = 2.0_rc13
openvpn / openvpn = 2.0_rc14
openvpn / openvpn = 2.0_rc15
openvpn / openvpn = 2.0_rc16
openvpn / openvpn = 2.0_rc17
openvpn / openvpn = 2.0_rc18
openvpn / openvpn = 2.0_rc19
openvpn / openvpn = 2.0_rc20
openvpn / openvpn = 2.0_rc21
openvpn / openvpn = 2.0_test1
openvpn / openvpn = 2.0_test2
openvpn / openvpn = 2.0_test3
openvpn / openvpn = 2.0_test5
openvpn / openvpn = 2.0_test6
openvpn / openvpn = 2.0_test7
openvpn / openvpn = 2.0_test8
openvpn / openvpn = 2.0_test9
openvpn / openvpn = 2.0_test10
openvpn / openvpn = 2.0_test11
openvpn / openvpn = 2.0_test12
openvpn / openvpn = 2.0_test14
openvpn / openvpn = 2.0_test15
openvpn / openvpn = 2.0_test16
openvpn / openvpn = 2.0_test17
openvpn / openvpn = 2.0_test18
openvpn / openvpn = 2.0_test19
openvpn / openvpn = 2.0_test20
openvpn / openvpn = 2.0_test21
openvpn / openvpn = 2.0_test22
openvpn / openvpn = 2.0_test23
openvpn / openvpn = 2.0_test24
openvpn / openvpn = 2.0_test26
openvpn / openvpn = 2.0_test27
openvpn / openvpn = 2.0_test29
openvpn / openvpn_access_server = 2.0.1
openvpn / openvpn_access_server = 2.0.2

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.