GHSA-46xh-7854-f568 CVE-2026-8205
Concrete CMS is vulnerable to authorization bypass in the Calendar Block
- Severity
- 0.0 / 10
- Medium · CVSS 4.0
- Exploit chance (EPSS)
- 0.21%
- Chance of exploitation in the next 30 days. Higher than 11.44% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-425 Direct Request ('Forced Browsing')
- Fix
9.5.1- Upgrade concrete5/concrete5 to this version or later
Description
Concrete CMS 9.5.0 and below is vulnerable to authorization bypass in the Calendar Block since action_get_events does not check canView on the calendar which results in restricted event details being disclosed.
Affected versions
Packagist
| Package | Vulnerable | Fixed in |
|---|---|---|
| concrete5/concrete5 | < 9.5.1 |
9.5.1 |
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.
concrete5/concrete5 Packagist → 9.5.1
- composer
composer require concrete5/concrete5:^9.5.1
Severity breakdown
CVSS 4.0 0.0
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N
- Attack vector
- Network
- Attack complexity
- Low
- Attack requirements
- Present
- 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
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-425: Direct Request ('Forced Browsing')
The web application does not adequately enforce appropriate authorization on all restricted URLs, scripts, or files.
How to prevent it
- Architecture and Design, Operation: Apply appropriate access control authorizations for each access to all restricted URLs, scripts or files.
- Architecture and Design: Consider using MVC based frameworks such as Struts.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-g82f-9pw7-773w Concrete CMS: PHP Object Injection via unserialize() calls | High | Also affects concrete5/concrete5 |
| GHSA-52pr-7vmf-2w7x Concrete CMS is vulnerable to PHP Object Injection via unserialize() calls in the Workflow, Form block, and File/Set components | High | Also affects concrete5/concrete5 |
| GHSA-q9fm-mpg8-8jqm Concrete CMS is vulnerable to Stored XSS via page name in the Atomik theme | Medium | Also affects concrete5/concrete5 |
| GHSA-jqvq-gv67-3567 Concrete CMS is vulnerable to IDOR + wrong-authorization-level in the Express association Reorder dialog | Medium | Also affects concrete5/concrete5 |
| GHSA-xjg6-5v39-v7fc Concrete CMS is vulnerable to CSRF via Backend\File::approveVersion | Medium | Also affects concrete5/concrete5 |
| GHSA-44q4-354f-c826 Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file approveVersion() | Medium | Also affects concrete5/concrete5 |
| GHSA-6qjh-p324-694f Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file rescanMultiple() | High | Also affects concrete5/concrete5 |
| GHSA-6fxm-r8p3-mx5c Concrete CMS is vulnerable to Cross Site Request Forgery (CSRF) at concrete/controllers/backend/file rescan() | High | Also affects concrete5/concrete5 |
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