CVE-2021-3287

CRITICALNVD 9.89.8—Weaponized

9.8

Zoho ManageEngine OpManager before 12.5.329 allows unauthenticated Remote Code Execution due to a general bypass in the deserialization class.

CVSS v3: 9.8
EG Score: 9.8(high)
EPSS: 99.5%
KEV: Not listed

Published

April 22, 2021

Last Modified

November 21, 2024

Advisory Details (2)

Auto-updated May 26, 2026

No patch confirmed yet.

generic

Read me | OpManager Help

https://www.manageengine.com/network-monitoring/help/read-me-complete.html#125329

generic

Packet Storm

http://packetstormsecurity.com/files/164231/ManageEngine-OpManager-SumPDU-Java-Deserialization.html

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-502Deserialization of Untrusted Data

Data Freshness Timeline

(refreshed 9× in last 7d / 17× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 17:59 UTCEG score recompute
2026-05-26 17:59 UTCGHSA enrichment
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-24 05:57 UTCOSV refresh

Publicly available exploits

(2 references)

Working exploit code is in the public domain (1 Metasploit module). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

Metasploitexploit/multi/http/opmanager_sumpdu_deserialization✓ verified
First seen Jul 26, 2021
ManageEngine OpManager SumPDU Java Deserialization
Open source ↗
Nucleihttp/cves/2021/CVE-2021-3287.yaml
First seen Jan 1, 2021
Zoho ManageEngine OpManager < 12.5.329 - Remote Code Execution
Open source ↗

Frequently asked(5)

What is CVE-2021-3287?

CVE-2021-3287 is a critical vulnerability published on April 22, 2021. Zoho ManageEngine OpManager before 12.5.329 allows unauthenticated Remote Code Execution due to a general bypass in the deserialization class.

When was CVE-2021-3287 disclosed?

CVE-2021-3287 was first published in the National Vulnerability Database on April 22, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-3287 actively exploited?

CVE-2021-3287 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-3287?

CVE-2021-3287 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-3287?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-3287, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-3287

Explore →

Is Your Infrastructure Affected by CVE-2021-3287?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Start Free Scan →Browse All CVEs

CVE-2021-3287

📅 Published

🔄 Last Modified

📋 Advisory Details (2)