CVE-2026-3988

Received Received - Intake

Denial of Service in GitLab GraphQL via Input Validation Flaw

Publication date: 2026-03-25

Last updated on: 2026-03-26

Assigner: GitLab Inc.

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.5 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an unauthenticated user to cause a denial of service by making the GitLab instance unresponsive due to improper input validation in GraphQL request processing.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-03-25

Last Modified

2026-03-26

Generated

2026-07-07

AI Q&A

2026-03-25

EPSS Evaluated

2026-07-05

NVD

CVE-2026-3988

EUVD

EUVD-2026-15937

Affected Vendors & Products

Vendor	Product	Version / Range
gitlab	gitlab	From 18.9.0 (inc) to 18.9.3 (exc)
gitlab	gitlab	18.10.0
gitlab	gitlab	From 18.5.0 (inc) to 18.8.7 (exc)
gitlab	gitlab	From 18.9.0 (inc) to 18.9.3 (exc)
gitlab	gitlab	From 18.5.0 (inc) to 18.8.7 (exc)
gitlab	gitlab	18.10.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-407	An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.

Attack-Flow Graph

Executive Summary

This vulnerability in GitLab CE/EE affects versions from 18.5 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1. It allows an unauthenticated user to cause a denial of service by making the GitLab instance unresponsive. The issue arises due to improper input validation in the processing of GraphQL requests.

Impact Analysis

The impact of this vulnerability is a denial of service (DoS) condition. An attacker who is not authenticated can exploit this flaw to make the GitLab instance unresponsive, potentially disrupting access to the service and affecting availability.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade your GitLab instance to a fixed version. Specifically, update to GitLab CE/EE versions 18.8.7 or later, 18.9.3 or later, or 18.10.1 or later, as these versions contain the remediation for the denial of service issue caused by improper input validation in GraphQL request processing.

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