October CMS safe mode bypass using Page template injection
Impact
An authenticated backend user with the editor.cms_pages, editor.cms_layouts, or editor.cms_partials permissions who would normally not be permitted to provide PHP code to be executed by the CMS due to cms.safe_mode being enabled can craft a special request to include PHP code in the CMS template.
This is not a problem for anyone who trusts their users with those permissions to usually write & manage PHP within the CMS by not having cms.safe_mode enabled. Still, it would be a problem for anyone relying on cms.safe_mode to ensure that users with those permissions in production do not have access to write and execute arbitrary PHP.
Patches
This issue has been patched in v3.4.15.
Workarounds
As a workaround, remove the specified permissions from untrusted users.
References
Credits to:
For more information
If you have any questions or comments about this advisory:
- Email us at hello@octobercms.com
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | october/system | >= 3.0.0, < 3.4.15 | 3.4.15 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N- Weakness (CWE)
CWE-94- Platform
- Composer
- Package
october/system- Disclosed
- 29.11.2023
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-q22j-5r3g-9hmh - CC BY 4.0
Vulnerability history: october/system
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 25
- First → latest
- 06.2020 09.2026
- Without a fix
- 0
- Exploited in attacks
- 1
Severity breakdown
- Critical 1
- High 8
- Medium 9
- Low 7
Disclosures per year
- 2020: 1
- 2021: 3
- 2022: 6
- 2023: 3
- 2024: 2
- 2025: 1
- 2026: 9
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