Vulnerability in october/cms (CVE-2021-21264)

Summary

Vulnerability in october/cms (CVE-2021-21264). Risk of unauthorized operations or information disclosure. Exploitable via cms.manage_pages. Mitigation: upgrade to 1.0.470 or later.

Original description

The description as published by the source.

Impact

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.

Patches

Issue has been patched in Build 472 (v1.0.472) and v1.1.2.

Workarounds

Apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.

References

Reported by ka1n4t

For more information

If you have any questions or comments about this advisory:

Email us at hello@octobercms.com

Threat assessment:

Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2021-21264 has been found in october/cms.
Attackers can target a specific entry point like cms.manage_pages over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade october/cms to 1.0.470 or later.
If unsure, ask your IT team or search "october/cms CVE-2021-21264" on the vendor's site.

CVE-2021-21264 (october/cms) — CWE-862
Attack vector: local
Attack surface: cms.manage_pages / cms.manage_layouts / cms.manage_partials / cms.enableSafeMode
Patched: 1.0.470 — apply immediately
Workaround: Apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.

❓ What is the problem

A vulnerability (CWE-862) exists in october/cms. Attackers reach the vulnerable code path via cms.manage_pages.

📍 Affected scope

Check the vendor advisory for the affected versions of october/cms. Attack surface: cms.manage_pages / cms.manage_layouts / cms.manage_partials / cms.enableSafeMode.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 1.0.470.

🛡️ Workaround

Workaround: Apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'october/cms' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'october/cms' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で october/cms を grep し、稼働しているサービス・バージョンを把握する。
2
Apply temporary workaround mitigate
```
Apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.
```
パッチが適用されるまでの応急処置として、Apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2. を実施。回避策の副作用 (機能低下) を確認した上で。
3
Apply patch patch
```
Upgrade october/cms to 1.0.470
```
ステージング環境で 1.0.470 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
4
Post-deployment verification verify
```
Confirm patched version is live in production
```
パッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Packagist october/cms

[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.1"},{"fixed":"1.1.2"}]}]

References

advisory nvd.nist.gov
package github.com
web github.com