CVE-2021-39937Network attack vector

Privilege escalation via cross-model memoization key collision

Published Dec 13, 2021 · Updated Aug 4, 2024

Improper access control in GitLab CE/EE before 14.3.6, 14.4 through 14.4.3, and 14.5 through 14.5.1 allows authenticated users to gain privileges. BulkMemberAccessLoad reuses a SafeRequestStore access-level key across projects and groups with the same numeric ID, causing one object's cached authorization to govern the other. Exploitation requires matching project and group IDs and both authorization checks in one request; documented GraphQL reads can cross access boundaries.

CVSS severity8.8
High
EPSS probability0.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper access control in GitLab CE/EE before 14.3.6, 14.4 through 14.4.3, and 14.5 through 14.5.1 allows authenticated users to gain privileges. BulkMemberAccessLoad reuses a SafeRequestStore access-level key across projects and groups with the same numeric ID, causing one object's cached authorization to govern the other. Exploitation requires matching project and group IDs and both authorization checks in one request; documented GraphQL reads can cross access boundaries.

The record

CVE
CVE-2021-39937
Published
Dec 13, 2021
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-269, T1068
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 13, 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=>=0.0, <14.3.6
  2. Affected versionversion=>=14.4, <14.4.4
  3. Affected versionversion=>=14.5, <14.5.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=0.0, <14.3.6; version=>=14.4, <14.4.4; version=>=14.5, <14.5.2

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
6.5NIST NVDAV:N/AC:L/Au:S/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-269Improper Privilege Management
T1068Exploitation for Privilege Escalation

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

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Your stack

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