GHSA-5pgf-h923-m958 CVE-2026-33160
Craft CMS may expose private assets through anonymous "generate transform" calls via transform URL
Medium
Packagist
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.36%
- Chance of exploitation in the next 30 days. Higher than 29.92% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Fix
5.9.14- Upgrade craftcms/cms to this version or later
Description
Summary
An unauthenticated user can call assets/generate-transform with a private assetId, receive a valid transform URL, and fetch transformed image bytes.
The endpoint is anonymous and does not enforce per-asset authorization before returning the transform URL.
Details
Root cause:
- Anonymous endpoint accepts user-controlled asset reference.
- It creates and returns a transform URL for that asset without checking access rights.
- If the transform output is reachable, guest users can read content derived from private assets.
Who is impacted:
- Installations where private source assets can be transformed and transform URLs are reachable.
Security consequence:
- Anonymous users can obtain content derived from private assets without authentication.
Resources
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| craftcms/cms | >= 5.0.0-RC1, < 5.9.14 |
5.9.14 |
| craftcms/cms | >= 4.0.0-RC1, < 4.17.8 |
4.17.8 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
craftcms/cms Packagist → 5.9.14
- composer
composer require craftcms/cms:^5.9.14
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- None
- Privileges required
- None
- User interaction
- None
- Confidentiality (vulnerable system)
- Low
- Integrity (vulnerable system)
- None
- Availability (vulnerable system)
- None
- Confidentiality (subsequent systems)
- None
- Integrity (subsequent systems)
- None
- Availability (subsequent systems)
- None
- Exploit maturity
- Unreported
CVSS 3.1 5.3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
Weakness
CWE-639: Authorization Bypass Through User-Controlled Key
The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
How to prevent it
- Architecture and Design: For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
- Architecture and Design, Implementation: Make sure that the key that is used in the lookup of a specific user's record is not controllable externally by the user or that any tampering can be detected.
- Architecture and Design: Use encryption in order to make it more difficult to guess other legitimate values of the key or associate a digital signature with the key so that the server can verify that there has been no tampering.
CWE-862: Missing Authorization
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
How to prevent it
- Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
- Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
- Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
- Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
- System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.
References
Advisories
Fixes and patches
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-7vrx-9684-xrf2 Craft CMS stores arbitrary content provided by unauthenticated users in session files | Medium Known exploited | Also affects craftcms/cms |
| GHSA-f3gw-9ww9-jmc3 Craft CMS Allows Remote Code Execution | Critical Known exploited | Also affects craftcms/cms |
| GHSA-x684-96hh-833x Craft CMS has a potential RCE with a compromised security key | High Known exploited | Also affects craftcms/cms |
| GHSA-2p6p-9rc9-62j9 Craft CMS has potential RCE when PHP `register_argc_argv` config setting is enabled | Critical Known exploited | Also affects craftcms/cms |
| GHSA-wg23-69c2-gjc8 Craft CMS: Passkey login accepts replayed WebAuthn assertions | Medium | Also affects craftcms/cms |
| GHSA-957r-qf9p-67xw Craft CMS: Arbitrary file read via SplFileObject in non-sandboxed template contexts | Medium | Also affects craftcms/cms |
| GHSA-596p-6jv8-775v Craft CMS: Authenticated leak of secret environment variables | Medium | Also affects craftcms/cms |
| GHSA-xxpx-f366-4xpq Craft CMS: Authorization bypass: view-only Categories user can modify category structure via structures/move-element | Medium | Also affects craftcms/cms |
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