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CVE-2021-40539· NVD / CVE Program· CNA mitre

Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execu

Noroxi assessment

Priority: Now (action score 99/100)

  • CISA has confirmed exploitation in the wild (Nov 3, 2021); it is known to be used in ransomware campaigns. Remediation deadline for US federal agencies: Nov 17, 2021.
  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • Probability of exploitation in the next 30 days: 98.9% (FIRST EPSS); higher than 99.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • According to the record, no fixed version is available yet.
  • Mentioned 5 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Patch today or shut off access. Until a fix is released, restrict access to the affected component and follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

Zoho ManageEngine ADSelfService Plus version 6113 and prior is vulnerable to REST API authentication bypass with resultant remote code execution.

CriticalCVSS 9.8 · v3.1KEVWeaponized No fix recorded
Published
Sep 7, 2021
Updated
Jun 17, 2026
EPSS
98.9% · 99th percentile

Report tools

JSON

Action score

99

Now

Patch today or shut off access.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
30 / 30 · 98.9%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Nov 17, 2021.

Known to be used in ransomware campaigns.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-40539

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
zohocorpmanageengine adselfservice plus

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zohocorp manageengine adselfservice plusbefore 6.1
  • zohocorp manageengine adselfservice plus6.1

Same product

zohocorp: all records

Other highest-scoring records for the same primary product.

  • CVE-2022-28810Zoho ManageEngine ADSelfService Plus before build 6122 allows a remote authenticated administrator to execute arbitrary operating OS commandKEV
    78This week
  • CVE-2021-28958Zoho ManageEngine ADSelfService Plus through 6101 is vulnerable to unauthenticated Remote Code Execution while changing the password.
    61This week
  • CVE-2021-33256A CSV injection vulnerability on the login panel of ManageEngine ADSelfService Plus Version: 6.1 Build No: 6101 can be exploited by an unaut
    59Plan

Published before and after this one in the same product

  • ← EarlierCVE-2021-37417Aug 30, 2021 · Zoho ManageEngine ADSelfService Plus version 6103 and prior allows CAPTCHA bypass due to improper parameter validation.
    40Plan
  • ← EarlierCVE-2021-37421Aug 30, 2021 · Zoho ManageEngine ADSelfService Plus 6103 and prior is vulnerable to admin portal access-restriction bypass.
    40Plan
  • Later →CVE-2021-37423Sep 10, 2021 · Zoho ManageEngine ADSelfService Plus 6111 and prior is vulnerable to linked applications takeover.
    40Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×5

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Metasploit moduleexploit/windows/http/manageengine_adselfservice_plus_cve_2021_40539ManageEngine ADSelfService Plus CVE-2021-40539exploit2021-09-07
Nuclei detection templateNuclei template CVE-2021-40539 —
Proof-of-concept repository on GitHubstars:22021-09-17
Proof-of-concept repository on GitHubstars:482021-11-03
Proof-of-concept repository on GitHubstars:02024-10-12
Proof-of-concept repository on GitHubstars:12024-10-12
Proof-of-concept repository on GitHubstars:22024-10-16

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Metasploit-1 d
  2. Published
  3. First PoC+9 d
  4. CISA KEV+56 d
  5. TodayOct 20, 2026+1869 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-706 · Use of Incorrectly-Resolved Name or Reference

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records