CVE-2021-43847Network attack vector

Private Space membership via missing invitation authorization

Published Dec 20, 2021 · Updated Aug 4, 2024

Improper authorization in HumHub before 1.9.3 and 1.10.0 through 1.10.2 allows remote authenticated users to join private Spaces. CreateController::actionInvite accepted a supplied Space and saved invitation data without checking the InviteUsers permission. A registered account is required, and successful abuse grants membership and access to content restricted to the private Space.

CVSS severity6.5
Medium
EPSS probability1.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper authorization in HumHub before 1.9.3 and 1.10.0 through 1.10.2 allows remote authenticated users to join private Spaces. CreateController::actionInvite accepted a supplied Space and saved invitation data without checking the InviteUsers permission. A registered account is required, and successful abuse grants membership and access to content restricted to the private Space.

The record

CVE
CVE-2021-43847
Published
Dec 20, 2021
Updated
Aug 4, 2024
Vendor
HumHub GmbH & Co. KG
Product
HumHub
Classifications
CWE-285, CWE-862, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=>= 1.10.0, < 1.10.3
  2. Affected versionversion=< 1.9.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

HumHub GmbH & Co. KG · HumHubversion=>= 1.10.0, < 1.10.3; version=< 1.9.3

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
6.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-285Improper Authorization
CWE-862Missing Authorization
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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