CVE-2021-27856Public exploitNetwork attack vector

Unauthenticated administrator access via passwordless hidden account

Published Dec 15, 2021 · Updated Sep 17, 2024

Authentication bypass in FatPipe WARP, IPVPN, and MPVPN allows remote attackers to gain administrator access through the web interface. The login servlet accepts the hidden cmuser centralized-management account with an empty password and returns an administrative session. No prior account is required; affected 10.1 releases are before 10.1.2r60p91, and affected 10.2 releases are before 10.2.2r42.

CVSS severity9.8
Critical
EPSS probability5.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FatPipe WARP, IPVPN, and MPVPN allows remote attackers to gain administrator access through the web interface. The login servlet accepts the hidden cmuser centralized-management account with an empty password and returns an administrative session. No prior account is required; affected 10.1 releases are before 10.1.2r60p91, and affected 10.2 releases are before 10.2.2r42.

The record

CVE
CVE-2021-27856
Published
Dec 15, 2021
Updated
Sep 17, 2024
Vendor
FatPipe
Product
MPVPN
Classifications
T1078.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.1 <10.1.2r60p91
  2. Affected versionversion=10.2 <10.2.2r42

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FatPipe · MPVPNversion=10.1 <10.1.2r60p91; version=10.2 <10.2.2r42
FatPipe · IPVPNversion=10.1 <10.1.2r60p91; version=10.2 <10.2.2r42
FatPipe · WARPversion=10.1 <10.1.2r60p91; version=10.2 <10.2.2r42

Published CVSS scores

9.8CERT/CCCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1078.001Valid Accounts Default Accounts

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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