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Memory LeakWeakness · CWE-401

CVE-2025-20224

MEDIUM · 5.8 CVSS v3.1 Published 2025-08-14
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
67/100
Remediation priority · Elevated
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
A vulnerability in the Internet Key Exchange Version 2 (IKEv2) module of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition. This vulnerability is due to improper parsing of IKEv2 packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to partially exhaust system memory, causing system instability like being unable to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

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 · moderate confidence

This is a memory leak vulnerability in Cisco ASA and FTD's IKEv2 module caused by improper parsing of crafted IKEv2 packets. An unauthenticated remote attacker can send a continuous stream of malicious IKEv2 packets to partially exhaust system memory, preventing new IKEv2 VPN sessions from being established and requiring a manual device reboot to recover.

MitigationApply the Cisco patch for this vulnerability when available; until then, consider restricting IKEv2 traffic at network borders using ACLs or edge filtering to limit exposure to untrusted networks.

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

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
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

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 Cisco device model and software
    Use the 'show version' command on the device console or SSH to confirm whether the device is a Cisco ASA or Firepower Threat Defense (FTD) appliance
    Affected if The device is not an ASA or FTD model, then this CVE does not apply
  2. Determine the installed software version
    Run 'show version' and locate the software version string (for ASA: 'asa' version X.X.X; for FTD: 'Cisco Threat Defense' version X.X)
    Affected if The version falls within the affected version range published by Cisco for CVE-2025-20224 - compare your version to Cisco's official advisory
  3. Verify IKEv2 VPN configuration exists
    Run 'show running-config crypto ikev2' or 'show vpn-sessiondb' to check if any IKEv2 policies, tunnels, or VPN configurations are defined on the device
    Affected if No IKEv2 configuration is present, the device may not be directly vulnerable to this specific memory leak trigger
  4. Check for memory exhaustion symptoms
    Run 'show memory' or 'show processes memory' to review available system memory; look for consistently decreasing free memory or high memory utilization by the IKEv2 process
    Affected if Free memory is abnormally low or continuously depleting, especially if correlated with IKEv2 process memory growth
  5. Review IKEv2 process and system logs
    Run 'show log' or 'show logging' to search for repeated IKEv2 error messages, crash indicators, or authentication failures from external sources
    Affected if Logs show abnormal patterns of IKEv2 packet processing errors or repeated connection attempts from untrusted IP addresses

A device is affected if it is a Cisco ASA or FTD running a version within the affected range AND has IKEv2 enabled, with observed memory exhaustion or abnormal IKEv2 activity in logs.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the Cisco patch for this vulnerability when available; until then, consider restricting IKEv2 traffic at network borders using ACLs or edge filtering to limit exposure to untrusted networks.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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Scan for this in your stack

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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-2025-20224 in production — separate from our analysis above.

No notes yet

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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
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