CVE-2021-39904Public exploitNetwork attack vector

Locked merge request modification via unchecked GraphQL mutations

Published Nov 4, 2021 · Updated Aug 4, 2024

Improper access control in GitLab CE/EE's GraphQL API allows remote authenticated users to alter a locked merge request. The discussionToggleResolve mutation accepts an author's discussion identifier and changes resolution state without enforcing the merge request lock; suggestion application likewise remains authorized. Exploitation requires the attacker to have created the merge request, but permits discussion changes and suggestion commits after a project owner locks it.

CVSS severity4.3
Medium
EPSS probability0.85%
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's GraphQL API allows remote authenticated users to alter a locked merge request. The discussionToggleResolve mutation accepts an author's discussion identifier and changes resolution state without enforcing the merge request lock; suggestion application likewise remains authorized. Exploitation requires the attacker to have created the merge request, but permits discussion changes and suggestion commits after a project owner locks it.

The record

CVE
CVE-2021-39904
Published
Nov 4, 2021
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-863, T1565.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 4, 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=>=13.1, <14.2.6
  2. Affected versionversion=>=14.3, <14.3.4
  3. Affected versionversion=>=14.4, <14.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=13.1, <14.2.6; version=>=14.3, <14.3.4; version=>=14.4, <14.4.1

Published CVSS scores

4.0NVDAV:N/AC:L/Au:S/C:N/I:P/A:N
4.3GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/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
T1565.001Stored Data Manipulation

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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