CVE-2021-21264

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.

At a glance

Exploitability

Can be exploited locally on the machine with an admin-level account, but needs a user to act. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-05-03 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 03:35 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.2 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-05-03 16:15 UTC

Last modified

2026-06-17 03:35 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-862 · Missing authorization

Record status

Modified

Affected

• Octobercms October ≤ 1.0.471
• Octobercms October ≤ 1.1.1

Attack profile CVSS 3.1 · 5.2

Attack vector

Local

Complexity

Low

Privileges needed

High

User interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-21264.md and follow it. Check whether this project is affected by CVE-2021-21264. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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