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Adaptive Security Appliance SoftwareOperating system · Cisco

CVE-2026-20015

MEDIUM · 5.8 CVSS v3.1 Published 2026-03-04
Fix available
A fix is available. Upgrade to 7.2.11 / 7.4.3 or later.
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 IKEv2 feature of Cisco Secure Firewall ASA Software and Cisco Secure FTD Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device that may impact the availability of services to devices elsewhere in the network. This vulnerability is due to a memory leak when parsing IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit could allow the attacker to exhaust resources, causing a DoS condition that will eventually require the device to be manually reloaded.

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 memory leak vulnerability in the IKEv2 packet parsing functionality of Cisco Secure Firewall ASA and FTD software allows unauthenticated remote attackers to send crafted IKEv2 packets that progressively exhaust device memory resources, eventually causing a denial of service condition requiring manual device reload.

MitigationApply the Cisco security patch for this vulnerability; implement rate limiting on IKEv2 connections as a temporary mitigation if patches cannot be immediately deployed; monitor device resource utilization.

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:>= 9.18.1, < 9.18.4.71>= 9.19.1, < 9.20.4.10>= 9.22.1.1, < 9.22.2.13>= 9.23.1, < 9.23.1.19
Secure Firewall Threat DefenseApplication
Affected:>= 7.2.0, < 7.2.11>= 7.3.0, < 7.4.3>= 7.6.0, < 7.6.4>= 7.7.0, < 7.7.11

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 ASA software version
    Run 'show version' on the ASA CLI and locate the 'Software Version' line in the output
    Affected if The version falls within any of these ranges: >= 9.18.1 and < 9.18.4.71; >= 9.19.1 and < 9.20.4.10; >= 9.22.1.1 and < 9.22.2.13; >= 9.23.1 and < 9.23.1.19
  2. Identify FTD software version
    Run 'show version' on the FTD CLI or access the FTD management center to view the software version
    Affected if The version falls within any of these ranges: >= 7.2.0 and < 7.2.11; >= 7.3.0 and < 7.4.3; >= 7.6.0 and < 7.6.4; >= 7.7.0 and < 7.7.11
  3. Verify IKEv2 is configured
    Run 'show run crypto ipsec' and 'show run crypto isakmp' to inspect active VPN crypto configurations; IKEv2 is enabled via 'crypto isakmp enable <interface>' and 'crypto isakmp policy <number>' with 'authentication' and 'encryption' settings
    Affected if IKEv2 (indicated by 'version 2' in the ISAKMP policy or 'crypto ikev2' commands) is enabled on any device interface
  4. Check current memory utilization
    Run 'show memory' on the ASA/FTD CLI to view used and free memory; compare current utilization against baseline
    Affected if Memory utilization is abnormally high or progressively increasing without corresponding traffic growth, which may indicate active exploitation

A device is affected if it runs a vulnerable ASA or FTD version AND has IKEv2 enabled, as the memory leak is triggered specifically by crafted IKEv2 packets.

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
Upgrade available Upgrade to 7.2.11 / 7.4.3 / 7.6.4 or later
Fixed in 7.2.117.4.37.6.4
Interim mitigation

Apply the Cisco security patch for this vulnerability; implement rate limiting on IKEv2 connections as a temporary mitigation if patches cannot be immediately deployed; monitor device resource utilization.

Recommended fix High confidence

ASA: 9.18.4.71, 9.20.4.10, 9.22.2.13, or 9.23.1.19 (depending on current branch); FTD: 7.2.11, 7.4.3, 7.6.4, or 7.7.11 (depending on current branch)

  1. Identify the currently running Cisco ASA or Firepower Threat Defense (FTD) version using 'show version' command
  2. Determine which version branch the current device is running (ASA: 9.18.x, 9.19.x, 9.22.x, or 9.23.x; FTD: 7.2.x, 7.3.x, 7.6.x, or 7.7.x)
  3. For ASA devices: Upgrade to the first fixed version in your branch: 9.18.x -> 9.18.4.71, 9.19.x/9.20.x -> 9.20.4.10, 9.22.x -> 9.22.2.13, 9.23.x -> 9.23.1.19
  4. For FTD devices: Upgrade to the first fixed version in your branch: 7.2.x -> 7.2.11, 7.3.x -> 7.4.3, 7.6.x -> 7.6.4, 7.7.x -> 7.7.11
  5. Before upgrading, backup the current configuration using 'write mem' or 'copy running-config startup-config'
  6. Schedule a maintenance window as the upgrade may require device reload
  7. After upgrade, verify the new version is running with 'show version' and confirm IKEv2 functionality is restored
  8. Monitor device memory usage post-upgrade to confirm the memory leak is resolved
Caveat Review Cisco release notes for version-specific caveats; some upgrades may require configuration changes or have interoperability implications with VPN peers

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

Fix this in Adaptive Security Appliance Software Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2026-20015 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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