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NVD / CVE Program· CNA VulnCheck

CVE-2026-56384: Craft CMS - Missing Authorization in assets/preview-thumb Endpoint

Noroxi assessment

Priority: Monitor (action score 21/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.33% (FIRST EPSS).
  • 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.
  • Fixed version: craftcms cms 4.17.8, 5.9.14.

Low priority for now. Upgrade to craftcms cms 4.17.8, 5.9.14 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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
Published
Jun 21, 2026
Updated
Oct 25, 2026
EPSS
0.3% · 26th percentile

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.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-56384

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

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-2026-112776Craft CMS 5.0.0 before 5.11.0 GraphQL Site-Scope Bypass via Mutations
    37Monitor
  • 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

Published before and after this one in the same product

  • ← EarlierCVE-2026-56382Jun 21, 2026 · Craft CMS - Remote Code Execution via Missing Config Sanitization in FieldsController
    34Monitor
  • ← EarlierCVE-2026-56383Jun 21, 2026 · Craft CMS - Stored XSS in Table Field via Row Heading Column Type
    18Monitor
  • Later →CVE-2026-56385Jun 21, 2026 · Craft CMS - Authorization Bypass in assets/preview-file Endpoint
    21Monitor

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.

No history yet (it accumulates with the daily EPSS job).

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-2026-8479873 days apartCraft CMS before 5.10.11 Authorization Bypass via actionDeleteForSite
    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

Show all references (2 more)

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

All records