CVE-2021-39876Public exploitNetwork attack vector

Private-group membership disclosure via assignee autocomplete

Published Mar 28, 2022 · Updated Aug 4, 2024

Improper authorization in GitLab allows remote authenticated users to disclose members of private groups through assignee autocomplete. The /autocomplete/users.json endpoint applies a weaker permission check than the project-members API and returns users inherited from an invited private group. A valid account with project access is required; affected releases are GitLab 11.3 through 14.1.6, 14.2 through 14.2.4, and 14.3.0.

CVSS severity4.3
Medium
EPSS probability0.94%
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 GitLab allows remote authenticated users to disclose members of private groups through assignee autocomplete. The /autocomplete/users.json endpoint applies a weaker permission check than the project-members API and returns users inherited from an invited private group. A valid account with project access is required; affected releases are GitLab 11.3 through 14.1.6, 14.2 through 14.2.4, and 14.3.0.

The record

CVE
CVE-2021-39876
Published
Mar 28, 2022
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-863, T1069
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 28, 2022CVE 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=>=11.3, <14.1.7
  2. Affected versionversion=>=14.2, <14.2.5
  3. Affected versionversion=>=14.3, <14.3.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=11.3, <14.1.7; version=>=14.2, <14.2.5; version=>=14.3, <14.3.1

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:P/I:N/A:N
4.3GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-863Incorrect Authorization
T1069Permission Groups Discovery

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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