dbcve.org
Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2013-5509

HIGH · 10.0 CVSS v2.0 Published 2013-10-13
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A vulnerability in the SSL implementation of Cisco ASA Software allows remote attackers to bypass authentication mechanisms by presenting a crafted X.509 client certificate. This enables unauthorized VPN or administrative access to the security appliance.

MitigationUpgrade Cisco ASA Software to version 9.0(2.6) or later for the 9.0 branch, or 9.1(2) or later for the 9.1 branch.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Adaptive Security Appliance SoftwareOperating system
Affected:= 9.0= 9.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/Au:N/C:C/I:C/A:C

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the device as a Cisco ASA
    Run the command 'show version' or 'show inventory' and look for 'Cisco Adaptive Security Appliance' in the output
    Affected if The device is a Cisco ASA appliance
  2. Determine the installed ASA software version
    Run 'show version' and locate the version string (for example, 'Version 9.0(1)' or 'Version 9.1(1)')
    Affected if The version starts with 9.0 or 9.1 (any subversion)
  3. Confirm SSL VPN or certificate-based authentication is configured
    Run 'show vpn-sessiondb' and 'show run crypto ca certificate' to check for active SSL VPN tunnels or imported client certificates
    Affected if SSL VPN (AnyConnect) or certificate-based authentication is enabled on the ASA
  4. Check for active administrative SSL sessions
    Run 'show vpn-sessiondb summary' or 'show webvpn session' to view current SSL VPN and admin sessions
    Affected if SSL VPN or webvpn sessions are active on the device

A Cisco ASA device running version 9.0.x or 9.1.x with SSL VPN or X.509 certificate authentication enabled is vulnerable to authentication bypass via crafted client certificates.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Cisco ASA Software to version 9.0(2.6) or later for the 9.0 branch, or 9.1(2) or later for the 9.1 branch.

Recommended fix High confidence

ASA 9.0(2.6) or later for 9.0.x branch; ASA 9.1(2) or later for 9.1.x branch

  1. Identify current ASA software version with 'show version' command
  2. Schedule a maintenance window for the upgrade procedure
  3. Download the fixed ASA software version from Cisco (9.0(2.6) for 9.0.x or 9.1(2) for 9.1.x) from tools.cisco.com
  4. Back up the current ASA configuration using 'write memory' and/or 'copy running-config tftp'
  5. Upload the new software image to the ASA using 'copy tftp flash'
  6. Set the new boot variable with 'boot system flash:/new-image-name'
  7. Reload the ASA with 'reload' command
  8. Verify the new version is installed with 'show version'
Caveat Point releases typically have minimal breaking changes; always test in a lab environment before production deployment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
15.0 hours of engineering $2,690
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,304.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2013-5509 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2013-5509 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data