CVE-2026-56385: Craft CMS - Authorization Bypass in assets/preview-file 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: 0.35% (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 versions >= 5.0.0-RC1, <= 5.9.13 and >= 4.0.0-RC1, <= 4.17.7 contain an authorization bypass in the assets/preview-file endpoint. The action does not enforce per-asset view authorization before returning preview content, allowing an authenticated low-privileged user to supply a controlled assetId for an asset they are not permitted to view and still receive preview response data (previewHtml), including a private preview image route containing the target private assetId. Fixed in 5.9.14 and 4.17.8.
- Published
- Jun 21, 2026
- Updated
- Oct 25, 2026
- EPSS
- 0.3% · 29th percentile
- CWE
- CWE-639
Report tools
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.
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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.
We use this product, ask for helpAffected 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
- 5.9.14, 4.17.8not affected
- 5.0.0-RC1 and later · before 5.9.14affected · semver
- 4.0.0-RC1 and later · before 4.17.8affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Packagist | craftcms/cms | from 4.0.0-RC1 · before 4.17.8 | 4.17.8 |
| Packagist | craftcms/cms | from 5.0.0-RC1 · before 5.9.14 | 5.9.14 |
Same product
craftcms: all recordsOther highest-scoring records for the same primary product.
- CVE-2026-112776Craft CMS 5.0.0 before 5.11.0 GraphQL Site-Scope Bypass via Mutations37Monitor
- CVE-2026-72785Craft CMS before 5.10.6 Authorization Bypass via structures/move-element37Monitor
- CVE-2026-84795Craft CMS before 5.10.11 Authentication Bypass via Admin Flag Inheritance36Monitor
Published before and after this one in the same product
- ← EarlierCVE-2026-56383Jun 21, 2026 · Craft CMS - Stored XSS in Table Field via Row Heading Column Type18Monitor
- ← EarlierCVE-2026-56384Jun 21, 2026 · Craft CMS - Missing Authorization in assets/preview-thumb Endpoint21Monitor
- Later →CVE-2026-56393Jun 21, 2026 · Craft CMS - Multiple Stored Cross-Site Scripting in Settings Names and Field Options18Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| craftcms cms | 4.17.8 | Vendor (CNA) |
| craftcms cms | 5.9.14 | Vendor (CNA) |
| Packagist:craftcms/cms | 4.17.8 | Package registry (OSV) |
| Packagist:craftcms/cms | 5.9.14 | Package 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 researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
- GCXWLPreporter
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2026-7999073 days apartGQL entry mutation `siteId` bypasses schema site scope, enabling cross-site content read/write/delete34Monitor
- CVE-2026-8479673 days apartCraft CMS 5.0.0-RC1 before 5.10.11 GraphQL Entry Mutation Site Scope Bypass34Monitor
- CVE-2026-5028310 days apartCraft CMS: Unauthorized Deletion of Source Assets During File Replacement21Monitor
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-639 · Authorization Bypass Through User-Controlled KeyCVSS 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
Root cause
The endpoint fetches the record by the ID sent in the request, but never checks whether the record belongs to the requesting user.
The bug in code
The whole CWE-639 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
const invoice = await Invoice.findById(req.params.id);
res.json(invoice);Fixed
const invoice = await Invoice.findOne({
id: req.params.id,
ownerId: req.user.id,
});
if (!invoice) return res.sendStatus(404);
res.json(invoice);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (2 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.