cms: Authorization Bypass Through User-Controlled Key
CVE-2026-28696 is a high-severity authorization bypass through user-controlled key vulnerability in cms from Craft CMS, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected cms versions: >= 4.0.0-RC1, < 4.17.0-beta.1; >= 5.0.0-RC1, < 5.9.0-beta.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Craft CMS to 4.17.0 or 5.9.0, whichever matches your release line, or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Craft CMS | cms | >= 4.0.0-RC1, < 4.17.0-beta.1; >= 5.0.0-RC1, < 5.9.0-beta.1 | Not stated |
| Craft CMS | Craft CMS | after 4.0.0 up to, but not including, 4.17.0; after 5.0.0 up to, but not including, 5.9.0; 4.0.0; 5.0.0 | 4.17.0, 5.9.0 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (github.com) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
Craft is a content management system (CMS). Prior to 4.17.0-beta.1 and 5.9.0-beta.1, the GraphQL directive @parseRefs, intended to parse internal reference tags (e.g., {user:1:email}), can be abused by both authenticated users and unauthenticated guests (if a Public Schema is enabled) to access sensitive attributes of any element in the CMS. The implementation in Elements::parseRefs fails to perform authorization checks, allowing attackers to read data they are not authorized to view. This vulnerability is fixed in 4.17.0-beta.1 and 5.9.0-beta.1.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: 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 developers prevent this class of flaw
- For each and every data access, ensure that the user has sufficient privilege to access the record that is being requested.
- 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.
- 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.
More Authorization Bypass Through User-Controlled Key vulnerabilities (CWE-639)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
- github.com/craftcms/cms/security/advisories/GHSA-7x43-mpfg-r9wjExploit, Mitigation
Patches and release notes
Other vulnerabilities in cms
- 9.8 Critical severity
- 8.8 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.2 High severity
- 8.8 High severity
Recent Authorization Bypass Through User-Controlled Key vulnerabilities
- 8.4 High severity
- 7.5 High severity
- 7.1 High severity
- 8.3 High severity
- 7.5 High severity
- 7.5 High severity
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