CVE-2021-39945Public exploitNetwork attack vector

Unauthorized merge request approval via stale permissions

Published Dec 13, 2021 · Updated Aug 4, 2024

GitLab 9.4 through 14.3.5, 14.4 through 14.4.3, and 14.5 through 14.5.1 allow remote authenticated users to approve merge requests after revocation. The approval API invokes MergeRequests::ApprovalService after a policy equates approval permission with update permission, leaving demoted authors authorized. A valid personal access token and prior merge-request authorship are required; successful requests change approval state and disclose private merge-request details.

CVSS severity2.7
Low
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

GitLab 9.4 through 14.3.5, 14.4 through 14.4.3, and 14.5 through 14.5.1 allow remote authenticated users to approve merge requests after revocation. The approval API invokes MergeRequests::ApprovalService after a policy equates approval permission with update permission, leaving demoted authors authorized. A valid personal access token and prior merge-request authorship are required; successful requests change approval state and disclose private merge-request details.

The record

CVE
CVE-2021-39945
Published
Dec 13, 2021
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-863
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=>=14.4, <14.4.4
  2. Affected versionversion=>=14.5, <14.5.2
  3. Affected versionversion=>=9.4, <14.3.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=14.4, <14.4.4; version=>=14.5, <14.5.2; version=>=9.4, <14.3.6

Published CVSS scores

4.0NIST NVDAV:N/AC:L/Au:S/C:N/I:P/A:N
2.7GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:H/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

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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