Impact When logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed.
Patches Issue has been patched in Build 472 (v1.0.472) and v1.1.2.
Workarounds Apply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2.
References - Reported by Anisio (Brazilian Information Security Analyst) - http://cve.circl.lu/cve/CVE-2021-3311
For more information If you have any questions or comments about this advisory: Email us at hello@octobercms.com
Threat assessment: <img width="699" alt="Screen Shot 2021-02-07 at 11 50 35 PM" src="https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png">
octobercms in a CMS platform based on the Laravel PHP Framework. In affected versions of the october/system package an attacker can exploit this vulnerability to bypass authentication and takeover of and user account on an October CMS server. The vulnerability is exploitable by unauthenticated users via a specially crafted request. This only affects frontend users and the attacker must obtain a Laravel secret key for cookie encryption and signing in order to exploit this vulnerability. The issue has been patched in Build 472 and v1.1.5.
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.managepages, cms.managelayouts, or cms.managepartials 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.