Skip to content

Bypass of fix for CVE-2020-15247, Twig sandbox escape

Low severity GitHub Reviewed Published Nov 22, 2020 in octobercms/october • Updated Jan 9, 2023

Package

composer october/cms (Composer)

Affected versions

= 1.0.469

Patched versions

1.0.470

Description

Impact

A bypass of CVE-2020-15247 (fixed in 1.0.469 and 1.1.0) was discovered that has the same impact as 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.

Patches

Issue has been patched in Build 470 (v1.0.470) and v1.1.1.

Workarounds

Apply octobercms/october@d34fb8a to your installation manually if unable to upgrade to Build 470 or v1.1.1.

References

Reported by ka1n4t

For more information

If you have any questions or comments about this advisory:

Threat assessment:

Screen Shot 2020-10-10 at 1 21 13 PM

### References - https://github.com/octobercms/october/security/advisories/GHSA-r89v-cgv7-3jhx - https://github.com/octobercms/october/commit/d34fb8ab51108495a9a651b841202d935f4e12f7 - https://github.com/advisories/GHSA-94vp-rmqv-5875 - https://nvd.nist.gov/vuln/detail/CVE-2020-26231
@LukeTowers LukeTowers published to octobercms/october Nov 22, 2020
Reviewed Nov 23, 2020
Published to the GitHub Advisory Database Nov 23, 2020
Last updated Jan 9, 2023

Severity

Low

Weaknesses

CVE ID

CVE-2020-26231

GHSA ID

GHSA-r89v-cgv7-3jhx

Source code

No known source code

Credits

Checking history
See something to contribute? Suggest improvements for this vulnerability.