CVE-2026-46386Network attack vector

Remote code execution via forged Marshal cookies

Published Jun 26, 2026 · Updated Jun 26, 2026

Code execution in OpenProject Docker images 8.3.0 through 17.2.3 and 17.3.0 through 17.3.1 allows remote attackers to execute Ruby code. The image hard-codes the Rails master key, so its two-factor-device cookie reader accepts attacker-forged Marshal objects. A valid account normally reaches the sink; enabled self-registration removes that gate, and gadget execution runs commands as the Puma worker.

CVSS severity9.9
Critical
EPSS probability0.49%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code execution in OpenProject Docker images 8.3.0 through 17.2.3 and 17.3.0 through 17.3.1 allows remote attackers to execute Ruby code. The image hard-codes the Rails master key, so its two-factor-device cookie reader accepts attacker-forged Marshal objects. A valid account normally reaches the sink; enabled self-registration removes that gate, and gadget execution runs commands as the Puma worker.

The record

CVE
CVE-2026-46386
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
OpenProject GmbH
Product
OpenProject
Classifications
CWE-798, CWE-1188, CWE-502, CWE-1392, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 2026Record 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=>= 17.3.0, < 17.3.2
  2. Affected versionversion=>= 8.3.0, < 17.2.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenProject GmbH · OpenProjectversion=>= 17.3.0, < 17.3.2; version=>= 8.3.0, < 17.2.4

Published CVSS scores

9.9GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-798Use of Hard-coded Credentials
CWE-1188Initialization of a Resource with an Insecure Default
CWE-502Deserialization of Untrusted Data
CWE-1392Use of Default Credentials
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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