CVE-2023-4658Network attack vector

Guest merge permission bypass

Published Dec 1, 2023 · Updated Apr 26, 2026

Incorrect authorization in GitLab EE versions 8.13 through 16.4.2, 16.5 through 16.5.2, and 16.6.0 allows remote authenticated users to merge as guests via group-granted permissions. GitLab applies the Allowed to merge permission from group membership without enforcing the intended guest authorization boundary. Exploitation requires a guest account and a group that grants the merge permission; the demonstrated impact is unauthorized repository changes, with no reported confidentiality or availability impact.

CVSS severity3.1
Low
EPSS probability0.39%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect authorization in GitLab EE versions 8.13 through 16.4.2, 16.5 through 16.5.2, and 16.6.0 allows remote authenticated users to merge as guests via group-granted permissions. GitLab applies the Allowed to merge permission from group membership without enforcing the intended guest authorization boundary. Exploitation requires a guest account and a group that grants the merge permission; the demonstrated impact is unauthorized repository changes, with no reported confidentiality or availability impact.

The record

CVE
CVE-2023-4658
Published
Dec 1, 2023
Updated
Apr 26, 2026
Vendor
GitLab
Product
GitLab
Classifications
CWE-863, T1548
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 1, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 26, 2026Record 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=16.5 <16.5.3
  2. Affected versionversion=16.6 <16.6.1
  3. Affected versionversion=8.13 <16.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=16.5 <16.5.3; version=16.6 <16.6.1; version=8.13 <16.4.3

Published CVSS scores

3.1GitLab CNACVSS:3.1/AV:N/AC:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-863CWE-863: Incorrect Authorization
T1548Abuse Elevation Control Mechanism

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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