CVE-2021-39882Network attack vector

User information disclosure via unauthenticated API endpoints

Published Oct 5, 2021 · Updated Aug 4, 2024

Improper authorization in affected GitLab CE/EE releases allows remote attackers to retrieve user information through REST API requests. The single-user, followers, and following endpoints accept sequential numeric user IDs without requiring authentication and return the corresponding account data. Network access and a known or guessed user ID are sufficient to enumerate accounts; the record reports disclosure only, not data modification or service interruption.

CVSS severity5.3
Medium
EPSS probability0.58%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Improper authorization in affected GitLab CE/EE releases allows remote attackers to retrieve user information through REST API requests. The single-user, followers, and following endpoints accept sequential numeric user IDs without requiring authentication and return the corresponding account data. Network access and a known or guessed user ID are sufficient to enumerate accounts; the record reports disclosure only, not data modification or service interruption.

The record

CVE
CVE-2021-39882
Published
Oct 5, 2021
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-319, T1087
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 5, 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

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=>=1.0, <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 privilegesunauthenticated

What is affected?

GitLab · GitLabversion=>=1.0, <14.1.7; version=>=14.2, <14.2.5; version=>=14.3, <14.3.1

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N
5.3GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
5.3NVDCVSS:3.1/AV:N/AC:L/PR:N/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-319Cleartext Transmission of Sensitive Information
T1087Account Discovery

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo