CVE-2026-56384Network attack vector

Private asset preview disclosure via missing authorization

Published Jun 21, 2026 · Updated Jun 21, 2026

Missing authorization in Craft CMS 4.0.0-RC1 through 4.17.7 and 5.0.0-RC1 through 5.9.13 exposes private preview links to remote authenticated users. The assets/preview-thumb action resolves an attacker-controlled assetId and generates preview HTML containing a signed fallback transform URL before checking asset-view permission. Control Panel access and a private asset outside the account’s allowed volumes are required; disclosure is limited to signed preview data without modification or service interruption.

CVSS severity5.3
Medium
EPSS probability0.33%
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 Craft CMS 4.0.0-RC1 through 4.17.7 and 5.0.0-RC1 through 5.9.13 exposes private preview links to remote authenticated users. The assets/preview-thumb action resolves an attacker-controlled assetId and generates preview HTML containing a signed fallback transform URL before checking asset-view permission. Control Panel access and a private asset outside the account’s allowed volumes are required; disclosure is limited to signed preview data without modification or service interruption.

The record

CVE
CVE-2026-56384
Published
Jun 21, 2026
Updated
Jun 21, 2026
Vendor
Pixel & Tonic
Product
Craft CMS
Classifications
CWE-862, CWE-200, T1213
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 21, 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=4.0.0-RC1 <4.17.8
  2. Affected versionversion=5.0.0-RC1 <5.9.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Pixel & Tonic · Craft CMSversion=4.0.0-RC1 <4.17.8; version=5.0.0-RC1 <5.9.14

Published CVSS scores

4.3VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
5.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

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-862Missing Authorization
CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1213Data from Information Repositories

Public exploit references

No public exploit references are available in this record.

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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