# CVE-2026-56384 — craftcms cms

> As of 2026-06-21, CVE-2026-56384 is a MEDIUM-severity vulnerability in craftcms cms, CVSS v3.1 4.3. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-56384 as of 2026-06-21; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-06-21

## What is CVE-2026-56384?

Craft CMS contains a missing authorization vulnerability in the assets/preview-thumb endpoint. A Control Panel user without permission to view a target private asset can call the endpoint with an attacker-controlled assetId and receive preview HTML containing a signed fallback transform preview link for that private asset, because no asset-view permission check is performed before preview generation. This affects versions >= 4.0.0-RC1, = 5.0.0-RC1, <= 5.9.13, and is fixed in 4.17.8 and 5.9.14.

The record classifies CVE-2026-56384 under weakness class [CWE-862](https://intel.threadlinqs.com/cwe/CWE-862). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 106 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 4.3 — MEDIUM (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N`)
- **CVSS v4.0 base score:** 5.3 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 2.2/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-06-21

## Is CVE-2026-56384 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- [craftcms](https://intel.threadlinqs.com/vendors/craftcms): cms

## How to fix CVE-2026-56384

No vendor patch reference has been recorded for CVE-2026-56384 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-56384

No threat campaign in the Threadlinqs corpus currently references CVE-2026-56384, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, GitHub Security Advisories. Last verified by Threadlinqs on 2026-06-22.

**Vendor advisory and patch**

- [github.com — vendor advisory](https://github.com/craftcms/cms/security/advisories/GHSA-x76w-8c62-48mg)
- [github.com — patch](https://github.com/craftcms/cms/commit/d30df3112220db1ffd6726a3ed11857014c7fb27)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/craft-cms-missing-authorization-in-assets-preview-thumb-endpoint)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-56384
Full detection coverage and IOCs for threats exploiting CVE-2026-56384 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp