How severe is CVE-2020-8599?

CVE-2020-8599 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which products are affected by CVE-2020-8599?

CVE-2020-8599 affects the following products: trendmicro apex one, trendmicro officescan.

How do I patch CVE-2020-8599?

No patch has shipped for CVE-2020-8599 yet — track the trendmicro apex one advisory for a fixed release and apply the workarounds below in the meantime.

How do I detect CVE-2020-8599 across my infrastructure?

Inventory every trendmicro apex one deployment and check each version against the affected-products list above.

How do I mitigate CVE-2020-8599 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Is CVE-2020-8599 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2020-8599, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2020-8599?

CVE-2020-8599 has an EPSS (Exploit Prediction Scoring System) score of 11.9%, placing it in the 96th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score warrants monitoring and prompt remediation.

Is CVE-2020-8599 in the CISA Known Exploited Vulnerabilities catalog?

Yes. CVE-2020-8599 (Trend Micro Apex One and OfficeScan Authentication Bypass Vulnerability) was added to CISA's Known Exploited Vulnerabilities (KEV) catalog on 2021-11-03. CISA required all US federal civilian agencies to remediate this vulnerability by 2022-05-03. The required action was: Apply updates per vendor instructions. Being listed in the KEV catalog is the strongest possible confirmation of active exploitation — treat this as a critical priority.

Which products and versions are affected by CVE-2020-8599?

CVE-2020-8599 affects trendmicro apex one (1 version, e.g. 2019); trendmicro officescan (1 version, e.g. xg). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2020-8599 published, and has it been updated?

CVE-2020-8599 was published on March 18, 2020 and was last updated on June 17, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🛡️

CISA KEV · ACTIVELY EXPLOITED

CRITICAL severity

CVE-2020-8599 — Apex One

CRITICAL

CVE-2020-8599 is a critical-severity (CVSS 9.8) vulnerability in trendmicro apex one. It is in CISA's Known Exploited Vulnerabilities catalog (added 2021-11-03) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.

Trend Micro Apex One (2019) and OfficeScan XG server contain a vulnerable EXE file that could allow a remote attacker to write arbitrary data to an arbitrary path on affected installations…

Published

Mar 18, 2020

Updated

Jun 17, 2026

Affected

2 products

Patched

See advisory

Exploits

1 known

Exploitation data as of Oct 23, 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 2021-11-03. Federal agencies were required to remediate by 2022-05-03.
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-2020-8599.

EPSS Exploitation Probability

via FIRST.org ↗

11.9%probability of exploitation in next 30 days

Moderate Risk0.00%

Lower risk than most CVEs96th percentile — riskier than 96% of all scored CVEsHighest risk

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

How urgent is this, really

CVE-2020-8599 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

Trend Micro Apex One (2019) and OfficeScan XG server contain a vulnerable EXE file that could allow a remote attacker to write arbitrary data to an arbitrary path on affected installations and bypass ROOT login. Authentication is not required to exploit this vulnerability.

Affected Products

2 products · 3 configurations

Application

apex onetrendmicro

1 version

2019

Application

officescantrendmicro

1 version

Exploits & PoCs

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

Trend Micro Apex One (2019) and OfficeScan XG server contain a vulnerabl…

cisa.govCISAJul 2021

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every trendmicro apex one deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2020-8599 yet — track the trendmicro apex one advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

O3 Security · Runtime Protection

Is CVE-2020-8599 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Protect my workloads How runtime protection works