CVE-2020-13270Public exploitNetwork attack vector

Restricted fork creation via unchecked API authorization

Published Jun 10, 2020 · Updated Aug 4, 2024

Missing authorization in GitLab CE/EE 11.3 through 12.9.7, 12.10 through 12.10.6, or 13.0 allows remote authenticated users to create fork relations. The POST /projects/:id/fork/:forked_from_id handler omits the permission check enforced by the UI and links an attacker-controlled project to a public project whose forking is restricted. A guest account and an existing attacker-controlled project are required; successful requests disclose the source project's fork count and default branch and create an unauthorized relationship.

CVSS severity7.5
High
EPSS probability1.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authorization in GitLab CE/EE 11.3 through 12.9.7, 12.10 through 12.10.6, or 13.0 allows remote authenticated users to create fork relations. The POST /projects/:id/fork/:forked_from_id handler omits the permission check enforced by the UI and links an attacker-controlled project to a public project whose forking is restricted. A guest account and an existing attacker-controlled project are required; successful requests disclose the source project's fork count and default branch and create an unauthorized relationship.

The record

CVE
CVE-2020-13270
Published
Jun 10, 2020
Updated
Aug 4, 2024
Vendor
GitLab
Product
GitLab
Classifications
CWE-862, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 10, 2020CVE 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=>=11.3, <12.9.8
  2. Affected versionversion=>=12.10, <12.10.7
  3. Affected versionversion=>=13.0, <13.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

GitLab · GitLabversion=>=11.3, <12.9.8; version=>=12.10, <12.10.7; version=>=13.0, <13.0.1

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.5GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/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-862Missing Authorization
T1190Exploit Public-Facing Application

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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