CVE Intelligence
CISA KEV Critical Authentication

CVE-2021-37415 — Zoho ManageEngine ServiceDesk Authentication Bypass Vulnerability

Zoho ManageEngine ServiceDesk Plus before 11302 is vulnerable to authentication bypass that allows a few REST-API URLs without authentication.

Published Sep 1, 2021 · Updated Oct 13, 2026 · Sources: CISA Known Exploited Vulnerabilities, CVE Program (cve.org) e CISA ADP, NIST National Vulnerability Database, GitHub Security Advisories · CNA: mitre

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

CISA KEV · Dec 1, 2021 Detection templates (Nuclei) · 1
How the score was calculated
  • Confirmed exploitation (CISA KEV)+35
  • Public exploit/PoC (nuclei)+4
  • EPSS 99.8% (30-day exploitation probability)+15
  • Technical severity (critical)+10
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Confirmed
CISA KEV, listed Dec 1, 2021
EPSS FIRST
99.83%
ahead of 100% of scored CVEs · Oct 14, 2026
Affects
Zohocorp
Manageengine Servicedesk Plus
CVSS base
9.8
Critical · 4 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Active
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

CISA required action CISA

Apply updates per vendor instructions.

US federal deadline: Dec 15, 2021 — passed 1766 day(s) ago

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Zohocorp Manageengine Servicedesk Plus).
  2. Treat as emergency remediation: the CVE is in CISA KEV (confirmed exploitation).
  3. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  4. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  5. EPSS ahead of 100% of scored CVEs: prioritize it in the patch queue.
  6. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Zohocorp Manageengine Servicedesk Plus version 11.1-11132version 11.1-11140version 11.1-11139version 11.1-11138version 11.1-11137version 11.1-11136version 11.1-11135version 11.1-11134
and 57 more version 11.1-11133version 11.1-11141version 11.1-11131version 11.1-11130version 11.1-11129version 11.1-11128version 11.1-11127version 11.1-11126version 11.1-11125version 11.1-11124version 11.1-11142version 11.1-11143version 11.1-11144version 11.2version 11.2-11200version 11.2-11201version 11.2-11202version 11.2-11203version 11.2-11204version 11.2-11205version 11.2-11206version 11.2-11207version 11.3version 11.3-11300version 11.3-11301version 11.1-11108version 11.0-11006version 11.0-11007version 11.0-11008version 11.0-11009version 11.0-11010version 11.0-11011version 11.1version 11.1-11100version 11.1-11101version 11.1-11102version 11.1-11103version 11.1-11104version 11.1-11105version 11.1-11106version 11.1-11107version 11.0-11005version 11.1-11109version 11.1-11110version 11.1-11111version 11.1-11112version 11.1-11113version 11.1-11114version 11.1-11115version 11.1-11116version 11.1-11117version 11.1-11118version 11.1-11119version 11.1-11120version 11.1-11121version 11.1-11122version 11.1-11123
Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
9.8 CVSS 3.1 Critical 3.9 5.9 nvd@nist.gov via NIST National Vulnerability Database
9.8 CVSS 3.1 Critical 3.9 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0 via NIST National Vulnerability Database
9.8 CVSS 3.1 Critical — — GitHub, Inc. via GitHub Security Advisories
9.8 CVSS 3.1 Critical — — CISA-ADP via CVE Program (cve.org) e CISA ADP
7.5 CVSS 2.0 High 10.0 6.4 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-306 · Missing Authentication for Critical Function

Other CVEs with this weakness →

CISA KEV details CISA

CISA lists a CVE once it has evidence of exploitation against real targets.

Listed
Dec 1, 2021
Federal deadline
Dec 15, 2021
passed 1766 day(s) ago
Ransomware use
Unknown

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a reference date.

Public exploits, PoCs and detection templates

Public code that demonstrates or tests the flaw raises the odds of mass exploitation — and Nuclei templates help find vulnerable assets in your environment.

Detection templates (Nuclei)

Warning: public PoCs are sometimes disguised malware. Use them only for authorized testing in an isolated environment. This portal does not host exploit code — it only points to the sources.

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 99.83%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
  • Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.
  • Hunt retroactively in logs from before Dec 1, 2021 (KEV listing): exploitation may have started earlier.
web/proxy/WAF logsnetwork IDS/IPSauthentication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · zohocorp/manageengine servicedesk plus
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · Published → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record published
    Oct 13, 2026
  • CVSS changed · 9.8
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Published
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Added to CISA KEV (detected)
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • Record created in this database
    Oct 13, 2026 · CISA Known Exploited Vulnerabilities
  • 2021
  • Added to CISA KEV catalog
    Nov 30, 2021 · CISA
  • CVE published
    Sep 1, 2021 · mitre

Source activity

Repeated readings are counted rather than listed.

  • 3× References added · Oct 13, 2026 – Oct 13, 2026
  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

5 on the record

Elsewhere on this site

Zohocorp
every CVE for this vendor
2021-12
what else CISA listed that month
Authentication
same class
CWE-306
other pages naming this weakness

Related CVEs (same products)

  • CVE-2022-47966 Zoho ManageEngine Multiple Products Remote Code Execution Vulnerability KEV Jan 18, 2023
  • CVE-2021-44077 Zoho ManageEngine ServiceDesk Plus Remote Code Execution Vulnerability KEV Nov 29, 2021
  • CVE-2019-8394 Zoho ManageEngine ServiceDesk Plus (SDP) File Upload Vulnerability KEV Feb 17, 2019

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No fixed version, patch or mitigation documented.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2021-37415 is "Zoho ManageEngine ServiceDesk Authentication Bypass Vulnerability", rated Critical. It affects Manageengine Servicedesk Plus (Zohocorp); versions are in the scope table. It is in CISA KEV: there is evidence of real-world exploitation. CVSS 9.8 describes technical severity. EPSS 99.83% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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