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CVE-2026-56384· NVD / CVE Program· CNA VulnCheck

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

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.

MediumCVSS 5.3 · v4.0—No exploit Fix available

Noroxi analysis

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Published
Jun 21, 2026
Updated
Jun 24, 2026
EPSS
0.3% · 24th percentile
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Report tools

JSON

Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulnCheck
5.3
NVD has not scored this yet; the score shown is the CNA’s.

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulnCheck). Independent of NVD's CPE analysis and usually ahead of it.

  • craftcms cms

    • 4.17.8, 5.9.14not affected
    • 4.0.0-RC1 and later · before 4.17.8affected · semver
    • 5.0.0-RC1 and later · before 5.9.14affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistcraftcms/cmsfrom 4.0.0-RC1 · before 4.17.84.17.8
Packagistcraftcms/cmsfrom 5.0.0-RC1 · before 5.9.145.9.14

Same product

craftcms: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-72785Craft CMS before 5.10.6 Authorization Bypass via structures/move-element
    37Monitor
  • CVE-2026-84795Craft CMS before 5.10.11 Authentication Bypass via Admin Flag Inheritance
    36Monitor
  • CVE-2026-92594Craft CMS before 5.11.0 Unauthenticated PII Disclosure via GraphQL
    34Monitor
  • CVE-2026-92593Craft CMS 5.10.0 before 5.10.13 Authenticated Remote Code Execution
    34Monitor
  • CVE-2026-92592Craft CMS before 4.18.6 Remote Code Execution via signed cookie
    34Monitor
  • CVE-2026-79987Low-privilege RCE through element-search eager loading
    34Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
craftcms cms4.17.8Vendor (CNA)
craftcms cms5.9.14Vendor (CNA)
Packagist:craftcms/cms4.17.8Package registry (OSV)
Packagist:craftcms/cms5.9.14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-8480173 days apartCraft CMS 5.0.0-RC1 before 5.10.11 Authentication Bypass via administrateUsers
    34Monitor
  • CVE-2026-5028410 days apartCraft CMS: Missing peer-permission check in `AssetsController::actionDeleteFolder` allows deletion of other users' assets
    28Monitor
  • CVE-2026-4401040 days apartCraft CMS: Missing Authorization in GraphQL Address Resolver Allows Cross-Scope PII Disclosure
    28Monitor
  • CVE-2026-4401240 days apartCraft CMS: Missing Volume Permission Check in AssetsController::actionShowInFolder Allows Information Disclosure
    28Monitor
  • CVE-2026-8479473 days apartCraft CMS 5.0.0 through 5.10.10 Authorization Bypass via assets/move-asset
    28Monitor
  • CVE-2026-8480073 days apartCraft CMS 5.0.0-RC1 before 5.10.11 File Overwrite via assets/replace-file
    28Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
X

Weakness class (CWE)

CWE-862 · Missing Authorization

CVSS vector

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records