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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 15 Apr 2022.
Secure Access Control SystemApplication · Cisco

CVE-2018-0147

CRITICAL · 9.8 CVSS v3.1 Published 2018-03-08
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
In the wild 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 Java deserialization used by Cisco Secure Access Control System (ACS) prior to release 5.8 patch 9 could allow an unauthenticated, remote attacker to execute arbitrary commands on an affected device. The vulnerability is due to insecure deserialization of user-supplied content by the affected software. An attacker could exploit this vulnerability by sending a crafted serialized Java object. An exploit could allow the attacker to execute arbitrary commands on the device with root privileges. Cisco Bug IDs: CSCvh25988.

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 Java deserialization vulnerability in Cisco Secure Access Control System (ACS) that allows remote, unauthenticated attackers to execute arbitrary commands with root privileges by sending a crafted serialized Java object. The vulnerability stems from insecure deserialization of user-supplied content in versions prior to 5.8 patch 9.

MitigationUpgrade Cisco ACS to release 5.8 patch 9 or later to remediate this vulnerability.

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
Secure Access Control SystemApplication
Affected:= 5.2\(0.3\)

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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. Verify Cisco ACS is installed
    Identify if Cisco Secure Access Control System is running in your environment. Check for the ACS service/process, or look for the installation directory typically at /opt/CSCOacs or C:\Program Files\Cisco\ACS or similar locations depending on OS.
    Affected if Cisco ACS software is present on the system
  2. Determine installed version
    Run the command 'show version' from the ACS CLI console, or check the About page in the ACS web interface, or inspect the file containing the ACS version information.
    Affected if The installed version is exactly 5.2(0.3)
  3. Identify exposed attack surface
    Determine if the ACS administrative interface (typically ports 443 or 8443) is accessible from the network. Check firewall rules, ACLs, or network exposure of the ACS web console.
    Affected if The ACS admin interface is reachable from untrusted networks without proper network segmentation

You are affected if Cisco ACS version 5.2(0.3) is installed and its administrative interface is network-accessible to potential attackers.

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 ACS to release 5.8 patch 9 or later to remediate this vulnerability.

Recommended fix High confidence

Cisco Secure Access Control System (ACS) 5.8 patch 9 or later

  1. 1. Back up the current Cisco ACS configuration using the backup feature in the ACS web interface or CLI.
  2. 2. Download Cisco Secure Access Control System version 5.8 patch 9 or later from the Cisco Software Download center (tools.cisco.com).
  3. 3. Upload the patch to the ACS appliance via the ACS web interface under Operations > Software Management > Upload Software, or via CLI using the ACS backup-server command.
  4. 4. Install the patch following Cisco's standard patch installation procedure for ACS 5.x.
  5. 5. After installation, verify the ACS version shows 5.8 patch 9 or later using the show version CLI command.
  6. 6. Validate that ACS services are running properly and test critical authentication flows.
Caveat Note: Cisco ACS reached End-of-Life (EOL) in 2019; consider migrating to Cisco Identity Services Engine (ISE) for long-term support

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

Fix this in Secure Access Control System Exploited in the wild — priority engagement
  • Consultation6.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,840
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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-2018-0147 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