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Adaptive Security ApplianceApplication · Cisco

CVE-2020-3528

HIGH · 7.5 CVSS v3.1 Published 2020-10-21
Fix available
A fix is available. Upgrade to 6.3.0.6 / 6.4.0.10 or later.
See remediation →
84/100
Remediation priority · High
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 OSPF Version 2 (OSPFv2) implementation of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability is due to incomplete input validation when the affected software processes certain OSPFv2 packets with Link-Local Signaling (LLS) data. An attacker could exploit this vulnerability by sending a malformed OSPFv2 packet to an affected device. A successful exploit could allow the attacker to cause an affected device to reload, resulting in a DoS 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 · high confidence

This is a denial-of-service vulnerability in Cisco ASA and FTD devices' OSPFv2 implementation. The flaw exists in incomplete input validation when processing OSPFv2 packets containing Link-Local Signaling (LLS) data. An attacker can send a malformed OSPFv2 packet to trigger the vulnerability, causing the affected device to reload.

MitigationApply the Cisco software update for CVE-2020-3528. If the patch is unavailable, consider filtering OSPF traffic at network boundaries or disabling OSPF on unused interfaces to reduce attack surface.

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 ApplianceApplication
Affected:< 9.6
Secure Firewall Threat DefenseApplication
Affected:< 6.3.0.6>= 6.4.0, < 6.4.0.10>= 6.5.0, < 6.5.0.5>= 6.6.0, < 6.6.1
Adaptive Security Appliance SoftwareOperating system
Affected:>= 9.8.0, < 9.8.4.26>= 9.9.0, < 9.9.2.80>= 9.10.0, < 9.10.1.44>= 9.12.0, < 9.12.4.4>= 9.13.0, < 9.13.1.13>= 9.14.0, < 9.14.1.19

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
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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 device model
    Run 'show version' or check the device model to confirm it is a Cisco Adaptive Security Appliance (ASA) or Firepower Threat Defense (FTD) device
    Affected if Device is not an ASA or FTD model (vulnerability only affects these product lines)
  2. Check ASA software version
    Run 'show version' to display the running software version. For ASA devices, compare the version number against the affected ranges: < 9.6, 9.8.0 to 9.8.4.25, 9.9.0 to 9.9.2.79, 9.10.0 to 9.10.1.43, 9.12.0 to 9.12.4.3, 9.13.0 to 9.13.1.12, or 9.14.0 to 9.14.1.18
    Affected if The ASA software version falls within any of the affected version ranges listed in the CVE
  3. Check FTD software version
    Run 'show version' to display the running FTD version. Compare against affected ranges: < 6.3.0.6, 6.4.0 to 6.4.0.9, 6.5.0 to 6.5.0.4, or 6.6.0 to 6.6.0
    Affected if The FTD software version falls within any of the affected version ranges listed in the CVE
  4. Verify OSPFv2 is enabled
    Run 'show ospf' or 'show run ospf' to check if OSPF routing is configured and enabled on the device
    Affected if OSPFv2 is not enabled (the vulnerability only triggers when processing OSPFv2 packets)
  5. Check OSPF interface configuration
    Run 'show ospf interface' to list interfaces participating in OSPF. Run 'show running-config | include ospf' to review OSPF configuration details
    Affected if OSPF is enabled on any interface - the device processes OSPF packets and is potentially vulnerable to malformed packets with LLS data

The device is affected if it is a Cisco ASA or FTD running a software version within the CVE-affected ranges AND has OSPFv2 enabled on one or more interfaces, as the vulnerability triggers during OSPFv2 packet processing with Link-Local Signaling data.

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
Upgrade available Upgrade to 6.3.0.6 / 6.4.0.10 / 6.5.0.5 or later
Fixed in 6.3.0.66.4.0.106.5.0.5
Interim mitigation

Apply the Cisco software update for CVE-2020-3528. If the patch is unavailable, consider filtering OSPF traffic at network boundaries or disabling OSPF on unused interfaces to reduce attack surface.

Fix this in Adaptive Security Appliance Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

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dbcve dependency scanner

Check whether your project pulls in CVE-2020-3528 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

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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-2020-3528 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data