Summary
Craft CMS: Low-privilege users could read private asset contents when editing an asset (IDOR)
A low-privileged authenticated user can read private asset content by calling assets/edit-image with an arbitrary assetId that they are not authorized to view.
The endpoint returns image bytes (or a preview redirect) without enforcing a per-asset view authorization check, leading to potential unauthorized disclosure of private files.
Details
Root cause:
- A user-controlled object reference (
assetId) is used to load and return sensitive content. - The action does not verify whether the current user is authorized to view that asset.
- This creates an authenticated IDOR / authorization bypass.
Resources
Impact
- Craft installations where private/non-public assets exist and low-privileged users can authenticate.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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craftcms/cms to 4.17.8 or later; craftcms/cms to 5.9.14 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-33158? CVE-2026-33158 is a medium-severity security vulnerability in craftcms/cms (composer), affecting versions >= 4.0.0-RC1, <= 4.17.7. It is fixed in 4.17.8, 5.9.14.
- Which versions of craftcms/cms are affected by CVE-2026-33158? craftcms/cms (composer) versions >= 4.0.0-RC1, <= 4.17.7 is affected.
- Is there a fix for CVE-2026-33158? Yes. CVE-2026-33158 is fixed in 4.17.8, 5.9.14. Upgrade to this version or later.
- Is CVE-2026-33158 exploitable, and should I be worried? Whether CVE-2026-33158 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-33158 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-33158?
- Upgrade
craftcms/cmsto 4.17.8 or later - Upgrade
craftcms/cmsto 5.9.14 or later
- Upgrade