TI-2026-40747 Aliases CVE-2026-56384 GHSA-x76w-8c62-48mg

Craft CMS - Missing Authorization in assets/preview-thumb Endpoint

LOW 24CWE-862Published 2026-06-21 · Updated 2026-06-24

Key facts

Attack vector: Network
Privileges required: Low
User interaction: None
Attack complexity: Low
Attack requirements: None
Impact type: Security bypass, Information disclosure
Confidentiality · integrity · availability: Low · None · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-862 and CWE-200.

Summary

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, <= 4.17.7 and >= 5.0.0-RC1, <= 5.9.13, and is fixed in 4.17.8 and 5.9.14.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00331 26th percentileScored 2026-11-07

Fix Fixed cms (craftcms): 4.17.8, 5.9.14craftcms/cms (Packagist): 4.17.8, 5.9.14

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Craft CMS	cms	4.0.0-RC1 to before 4.17.8; 5.0.0-RC1 to before 5.9.14	4.17.8, 5.9.14	Patch available	CNA
—	craftcms/cms (Packagist)	4.0.0-RC1 to before 4.17.8	4.17.8	Patch available	GHSA-x76w-8c62-48mg
—	craftcms/cms (Packagist)	5.0.0-RC1 to before 5.9.14	5.9.14	Patch available	GHSA-x76w-8c62-48mg

cms VendorCraft CMS Affected 4.0.0-RC1 to before 4.17.8; 5.0.0-RC1 to before 5.9.14 Fixed in 4.17.8, 5.9.14 Patch available CNA
craftcms/cms (Packagist) Vendor— Affected 4.0.0-RC1 to before 4.17.8 Fixed in 4.17.8 Patch available GHSA-x76w-8c62-48mg
craftcms/cms (Packagist) Vendor— Affected 5.0.0-RC1 to before 5.9.14 Fixed in 5.9.14 Patch available GHSA-x76w-8c62-48mg

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPE	Versions	Role	Vendor
cpe:2.3:a:craftcms:craft_cms::::::::	—	—	Craft CMS

cpe:2.3:a:craftcms:craft_cms:*:*:*:*:*:*:*:* Versions — — ·Craft CMS

Remediation

Fix · CNA cms (craftcms) Fixed in 4.17.8, 5.9.14
Fix · GHSA-x76w-8c62-48mg craftcms/cms (Packagist) Fixed in 4.17.8 Advisory →
Fix · GHSA-x76w-8c62-48mg craftcms/cms (Packagist) Fixed in 5.9.14 Advisory →

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-06-21
craftcms cms 4.17.8, 5.9.14
2 records Highest priority Priority LOW 2 LOW
Other records, highest priority first
- TI-2026-40748 Craft CMS - Authorization Bypass in assets/preview-file EndpointPriority LOW 24
Show all 2 records →

Timeline

2026-10-02 Threatist record created from CVE-2026-56384
2026-10-03 Alias added: GHSA-x76w-8c62-48mg

References

Patch 1

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

Advisory 2

Other 1

https://github.com/craftcms/cms

TI-2025-23503 Craft CMS Allows Remote Code Execution KEVCVSS 3.1CRITICAL 10.0
TI-2024-37138 RCE when PHP `register_argc_argv` config setting is enabled in craftcms/cms KEVCVSS 4.0CRITICAL 9.3
TI-2025-16994 Potential RCE with a compromised security key in craft/cms KEVCVSS 3.1HIGH 8.1
TI-2025-24595 Craft CMS stores user-provided content in session files KEVCVSS 4.0MEDIUM 6.9
TI-2023-22284 Craft CMS Remote Code Execution vulnerability CVSS 3.1CRITICAL 10.0
TI-2024-25171 Craft CMS up to v3.7.31 was discovered to contain a SQL injection vulnerability via the GraphQL API endpoint. CVSS 3.1CRITICAL 9.8

See all 203 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences