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Medium

Security advisory

Type: advisorySources: OSVCVE: CVE-2021-21264

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2021-21264
Confirmed fixed CVEs
Not specified
Updated in this feed
31 Oct 2026, 11:31 UTC · Revision 1

Source evidence

CVE-2021-21264

core-osv · Original source

Published 3 May 2021, 16:15 UTC

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.

osv:CVE-2021-21264
Complete source record
{
  "id": "8c47e415c0eda161ecd9fae96971df71efda30db4b74a4862f6d065d579deda1",
  "url": "https://osv.dev/vulnerability/CVE-2021-21264",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-21264",
    "summary": "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.",
    "evidence": "osv:CVE-2021-21264",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-21264",
      "aliases": [
        "CVE-2021-21264",
        "GHSA-fcr8-6q7r-m4wg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/octobercms/october",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "last_affected": "61e49d9e0b5f7e5323353f254d4ff12905bbe573"
                },
                {
                  "introduced": "6389554935644bfbb15db5fcd0ce4db6cbe3d103"
                },
                {
                  "last_affected": "24d95a208bf4a0840d7b631a87ad1ce3fb4a5ed3"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "1.0.471"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:octobercms:october:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.1.0"
                      },
                      {
                        "last_affected": "1.1.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
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          "versions": [
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-21264.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:27.818704764Z",
      "provider": "osv",
      "references": [
        "https://github.com/octobercms/october/security/advisories/GHSA-fcr8-6q7r-m4wg"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-21264",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385386,
  "published_at": "2021-05-03T16:15:07.51+00:00"
}