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CISA KEV · ACTIVELY EXPLOITED
CRITICAL severity

CVE-2018-0147

CRITICAL

CVE-2018-0147 is a critical-severity (CVSS 9.8) Improper Input Validation vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2022-03-25) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

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…

Published
Updated
Affected
1 product
Patched
See advisory
Exploits
2 known
Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, CISA KEV, FIRST.org (EPSS)

Exploitation Status

Actively exploited in the wild

  • Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2022-03-25. Federal agencies were required to remediate by 2022-04-15.
  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2018-0147.

EPSS Exploitation Probability

via FIRST.org ↗
18.2%probability of exploitation in next 30 days
Moderate Risk0.00%
Lower risk than most CVEs97th percentile — riskier than 97% of all scored CVEsHighest risk
0.00%7.50%15.0%22.5%4.0%4.0%18.2%18.2%18.2%Apr 26Sep 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2018-0147 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 394,803 CVEs with a current EPSS score, this one falls in the 10–50% band (highlighted). Counts from FIRST.org, log-scaled.

Description

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.

Affected Products

1 product · 1 configurations
Application
secure access control systemcisco
1 version
5.2\(0.3\)
Exploits & PoCs
2

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Vulnerability
  1. Detect

    Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).

  2. Remediation status

    No fixed release is recorded for CVE-2018-0147 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.

  3. Mitigate without a patch

    Do not deserialise data from untrusted sources: where the format allows it, restrict deserialisation to an explicit allowlist of expected types, and prefer a data-only format (JSON, Protobuf) over one that can reconstruct arbitrary objects until you can upgrade.

Frequently Asked Questions

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.
O3 Security · Impact-Aware SCA

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CVE-2018-0147: Critical 9.8 (KEV)