High

Unauthenticated DoS in GitLab GraphQL request processing

IdentifiersCVE-2026-3988CWE-20

CVE-2026-3988 is a denial-of-service vulnerability in GitLab CE/EE caused by improper input validation in GraphQL request processing. It affects all versions from 18.5 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1. A remote, unauthenticated attacker can send crafted GraphQL requests that trigger excessive resource consumption during request handling, causing the GitLab instance to become unresponsive.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to exhaust server resources through malformed or abusive GraphQL requests, resulting in denial of service. The primary impact is loss of availability of the GitLab instance, with users unable to access or use the service while it is unresponsive.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure to the GraphQL interface by restricting network access to GitLab, placing the instance behind rate limiting or a reverse proxy/WAF, and monitoring for abusive or anomalous GraphQL request patterns that may indicate resource-exhaustion attempts. These measures may reduce exploitability but do not fully remediate the underlying flaw.

Remediation

Patch, then assume compromise.

Upgrade GitLab CE/EE to a fixed release: 18.8.7 or later in the 18.8 series, 18.9.3 or later in the 18.9 series, or 18.10.1 or later in the 18.10 series. If running an affected version from 18.5 onward, apply the vendor-provided patched version appropriate to the deployed release track.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

GitLabGitlabapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

9 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

9 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity8

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-3988

NVD

nvd.nist.gov/vuln/detail/CVE-2026-3988

MITRE CWE · CWE-20

cwe.mitre.org

Vendor Advisory

about.gitlab.com/releases/2026/03/25/patch-release-gitlab-18-10-1-released

Permissions Required

hackerone.com/reports/3597342