Bypass of fix for CVE-2020-26231, Twig sandbox escape
Key facts
- Attack vector
- Local
- Privileges required
- High
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-862.
Summary
October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 & CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write & manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write & execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| October CMS | october | 1.0.471; 1.1.1 | — | No fix listed | CNA |
| — | october/cms (Packagist) | 1.0.471 to before 1.0.472 | 1.0.472 | Patch available | GHSA-fcr8-6q7r-m4wg |
| — | october/cms (Packagist) | 1.1.1 to before 1.1.2 | 1.1.2 | Patch available | GHSA-fcr8-6q7r-m4wg |
- october VendorOctober CMS Affected 1.0.471; 1.1.1 Fixed in — No fix listed CNA
- october/cms (Packagist) Vendor— Affected 1.0.471 to before 1.0.472 Fixed in 1.0.472 Patch available GHSA-fcr8-6q7r-m4wg
- october/cms (Packagist) Vendor— Affected 1.1.1 to before 1.1.2 Fixed in 1.1.2 Patch available GHSA-fcr8-6q7r-m4wg
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:* | up to 1.0.471; 1.1.0 – 1.1.1 | Vulnerable | October CMS |
- cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:* Versions up to 1.0.471; 1.1.0 – 1.1.1 Vulnerable ·October CMS
Remediation
- Fix · GHSA-fcr8-6q7r-m4wg october/cms (Packagist) Fixed in 1.0.472 Advisory →
- Fix · GHSA-fcr8-6q7r-m4wg october/cms (Packagist) Fixed in 1.1.2 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-21264
- 2026-10-03 Alias added: GHSA-fcr8-6q7r-m4wg
References
More October CMS October vulnerabilities
- TI-2021-12316 Account Takeover in Octobercms KEVCVSS 3.1CRITICAL 9.1
- TI-2021-12318 Arbitrary code execution in october/system CVSS 3.1HIGH 8.8
- TI-2017-14456 October CMS build 412 is vulnerable to PHP code execution in the file upload… CVSS 3.0HIGH 7.2
- TI-2023-23545 A Cross-Site Scripting (XSS) vulnerability in installation of October v.3.4.16 allows an… CVSS 3.1MEDIUM 5.4
- TI-2023-19223 An arbitrary file upload vulnerability in October CMS v3.4.4 allows attackers to execute… CVSS 3.1MEDIUM 5.4
- TI-2024-30847 October 3.6.30 allows an authenticated admin account to upload a PDF file containing… CVSS 3.1MEDIUM 4.7
Sources
- CVE-2021-21264 · CVE Program
- CVE-2021-21264 · NVD
- FIRST EPSS
- GHSA-fcr8-6q7r-m4wg · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences