What is CVE-2021-3287?

CVE-2021-3287 is a critical-severity vulnerability in Zohocorp Manageengine Opmanager, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2021-04-22.

How severe is CVE-2021-3287?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2021-3287 known to be exploited?

7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Deserialization in Zohocorp Manageengine Opmanager

CVE-2021-3287

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

Vulnerability class: Insecure Deserialization

Published 2021-04-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.513 (98.9th percentile), scored 2026-10-19.

High probability of exploitation in the next 30 days — patch promptly. 99th percentile — 98.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.513 · newest: 0.513 · change: 0.000

Affected products

Zohocorp Manageengine Opmanager — versions 12.5

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

Public proof-of-concept exploits

References

www.manageengine.com/network-monitoring/help/read-me-complete.html (Release Notes, Vendor Advisory)
packetstormsecurity.com/files/164231/ManageEngine-OpManager-SumPDU-Java-Deseria… (Exploit, VDB Entry, Third Party Advisory)

Frequently asked questions

What is CVE-2021-3287?: CVE-2021-3287 is a critical-severity vulnerability in Zohocorp Manageengine Opmanager, classified under Deserialization of Untrusted Data. CVSS score: 9.8/10. Published 2021-04-22.
How severe is CVE-2021-3287?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-3287 known to be exploited?: 7 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.