CVE-2013-5509 Auth bypass in n/a

What is CVE-2013-5509?

CVE-2013-5509 is a critical authentication bypass vulnerability in Cisco Adaptive Security Appliance Software, published on 13 Oct 2013. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

The SSL implementation in Cisco Adaptive Security Appliance (ASA) Software 9.0 before 9.0(2.6) and 9.1 before 9.1(2) allows remote attackers to bypass authentication, and obtain VPN access or administrative access, via a crafted X.509 client certificate, aka Bug ID CSCuf52468.

Weakness: CWE-264

Which versions are affected by CVE-2013-5509?

It affects 1 product.

Products include Cisco Adaptive Security Appliance Software.

How do I fix CVE-2013-5509?

No fix has been published for CVE-2013-5509 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2013-5509 being exploited?

There is no known exploitation of CVE-2013-5509 in the wild and no public exploit code.

Other vulnerabilities in Cisco Adaptive Security Appliance Software

• CVE-2025-20333 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow Exploited Critical 9.9
• CVE-2016-6366 Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow Exploited High 8.8
• CVE-2026-20349 Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection Exploited High 8.6
• CVE-2024-20353 Cisco ASA and FTD Denial of Service Exploited High 8.6
• CVE-2016-6367 Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution Exploited High 7.8

All Cisco Adaptive Security Appliance Software vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-m6gf-4gcj-j6c4.