CVE-2023-3917Public exploitNetwork attack vector

Pipeline denial via branch-named tag collision

Published Sep 29, 2023 · Updated Apr 29, 2026

Denial of service in GitLab EE and CE before 16.2.8, 16.3 through 16.3.4, and 16.4.0 allows remote authenticated users to fail pipelines. GitLab permits a Developer to push a tag named refs/heads/main, causing pipeline ref resolution to withhold protected CI/CD variables. Developer access to a project with protected variables is required; affected pipelines lose those variables and can fail.

CVSS severity4.3
Medium
EPSS probability0.78%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in GitLab EE and CE before 16.2.8, 16.3 through 16.3.4, and 16.4.0 allows remote authenticated users to fail pipelines. GitLab permits a Developer to push a tag named refs/heads/main, causing pipeline ref resolution to withhold protected CI/CD variables. Developer access to a project with protected variables is required; affected pipelines lose those variables and can fail.

The record

CVE
CVE-2023-3917
Published
Sep 29, 2023
Updated
Apr 29, 2026
Vendor
GitLab
Product
GitLab
Classifications
CWE-1287, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 29, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 29, 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=0 <16.2.8
  2. Affected versionversion=16.3 <16.3.5
  3. Affected versionversion=16.4 <16.4.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=0 <16.2.8; version=16.3 <16.3.5; version=16.4 <16.4.1

Published CVSS scores

4.3GitLab Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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-1287Improper Validation of Specified Type of Input
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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