How severe is CVE-2026-56385?

No CVSS score has been assigned to CVE-2026-56385 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-56385?

CVE-2026-56385 affects the following packages: craftcms/cms (Packagist), craftcms/cms (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-56385?

Update craftcms/cms to 5.9.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56385 is resolved across your whole dependency graph.

How do I detect CVE-2026-56385 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-56385 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2026-56385 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-56385 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-56385?

CVE-2026-56385 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 30th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-56385?

CVE-2026-56385 is classified as CWE-639 (CWE-639). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-56385 published, and has it been updated?

CVE-2026-56385 was published on June 21, 2026 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-56385 — cms

Fix: craftcms/cms@d30df31

CVE-2026-56385 is a CWE-639 vulnerability in craftcms/cms. A fix is available for craftcms/cms — see the affected versions and patch details below.

Craft CMS - Authorization Bypass in assets/preview-file Endpoint

Also known asGHSA-44px-qjjc-xrhq

Published

Jun 21, 2026

Updated

Oct 28, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 3, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-56385.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs30th percentile — riskier than 30% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

2 pkgs affected

🐘craftcms/cms🐘craftcms/cms

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Summary

An authenticated low-privileged user can call assets/preview-file for an asset they are not authorized to view and still receive preview response data (previewHtml) for that private asset.

The returned preview HTML included a private preview image route containing the target private assetId, even though canView was false for the attacker account.

Details

assets/preview-file accepts a maliciously controlled assetId and renders preview output.
The action does not enforce per-asset view authorization prior to returning preview content.
As a result, an authenticated user without asset-view permission can still obtain private preview output.

This affects Craft installations with authenticated users of mixed privilege levels with private assets.

Resources

d30df3112220db1ffd6726a3ed11857014c7fb27
b1cddf72c98a

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`craftcms/cms`	≥ 5.0.0-RC1&&< 5.9.14	5.9.14`composer require craftcms/cms:^5.9.14`
🐘Packagist	`craftcms/cms`	≥ 4.0.0-RC1&&< 4.17.8	4.17.8`composer require craftcms/cms:^4.17.8`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for craftcms/cms, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update craftcms/cms to 5.9.14 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-56385 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

### Summary An authenticated low-privileged user can call `assets/preview-file` for an asset they are not authorized to view and still receive preview response data (`previewHtml`) for that private asset. The returned preview HTML included a private preview image route containing the target private `assetId`, even though `canView` was `false` for the attacker account. ### Details 1. `assets/preview-file` accepts a maliciously controlled `assetId` and renders preview output. 2. The action does not enforce per-asset view authorization prior to returning preview content. 3. As a result, an a

O3 Security · Impact-Aware SCA

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