CVE-2021-21264CWE-862

Bypass of fix for CVE-2020-26231, Twig sandbox escape

Medium · published May 3, 2021

CVSS v3.1
5.2
EPSS
0%
Percentile
17.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.2 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L
CVSS v4.0
Not supplied
EPSS
0.00262 · 17.1th percentile
Weakness
CWE-862 · Missing Authorization
Published
2021-05-03T16:00Z
EPSS history
Timeline
  • 03 MAY 16:00Z
    Bypass of fix for CVE-2020-26231, Twig sandbox escape
    cvelistv5