Summary
Twig Sandbox Escape by authenticated users with access to editing CMS templates when safemode is enabled.
Workarounds
Apply https://github.com/octobercms/october/compare/106daa2930de4cebb18732732d47d4056f01dd5b...7cb148c1677373ac30ccfd3069d18098e403e1ca to your installation manually if unable to upgrade to Build 469.
References
Reported by ka1n4t
For more information
If you have any questions or comments about this advisory:
- Email us at [email protected]
Threat assessment:
Impact
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.
The application does not perform an authorization check before performing a sensitive operation. Typical impact: unauthorized access to restricted functionality or data.
CVE-2020-15247 has a CVSS score of 5.2 (Medium). The vector is requires local access, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.0.469); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Issue has been patched in Build 469 (v1.0.469) and v1.1.0.
Frequently Asked Questions
- What is CVE-2020-15247? CVE-2020-15247 is a medium-severity missing authorization vulnerability in october/cms (composer), affecting versions >= 1.0.319, < 1.0.469. It is fixed in 1.0.469. The application does not perform an authorization check before performing a sensitive operation.
- How severe is CVE-2020-15247? CVE-2020-15247 has a CVSS score of 5.2 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of october/cms are affected by CVE-2020-15247? october/cms (composer) versions >= 1.0.319, < 1.0.469 is affected.
- Is there a fix for CVE-2020-15247? Yes. CVE-2020-15247 is fixed in 1.0.469. Upgrade to this version or later.
- Is CVE-2020-15247 exploitable, and should I be worried? Whether CVE-2020-15247 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2020-15247 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2020-15247? Upgrade
october/cmsto 1.0.469 or later.