Vulnerability Database

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Total vulnerabilities in the database

Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission — craftcms / cms

Exposure of Sensitive Information to an Unauthorized Actor

Summary

A user with Control Panel access but without permission to view a target private asset can call assets/preview-thumb and receive preview HTML that contains a signed fallback transform link for that private asset.

Details

Root-cause analysis:

  1. The endpoint accepts an attacker-controlled assetId.
  2. Asset is resolved, and thumbnail HTML is returned.
  3. No explicit asset-view permission check is performed before preview generation.

Impact

Type:

  1. Missing authorization
  2. Unauthorized preview-link disclosure

Affected deployments:

  1. Craft sites with control panel users who have partial permissions and private assets.

Security consequence:

  1. A control panel user without asset-view permission can still obtain signed preview transform link data for private assets.
  2. This may increase private asset exposure risk depending on deployment and endpoint chaining.

Resources

https://github.com/craftcms/cms/commit/d30df3112220db1ffd6726a3ed11857014c7fb27

  • Published: Jul 6, 2026
  • Updated: Jul 7, 2026
  • GHSA: GHSA-x76w-8c62-48mg
  • Severity: Medium
  • Exploit:
  • CISA KEV:

No technical information available.

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.