Vulnerability in Concrete CMS (CVE-2021-22951)

Summary

Vulnerability in Concrete CMS (CVE-2021-22951). Confidential information can be exposed externally.

Original description

The description as published by the source.

Unauthorized individuals could view password protected files using view_inline in Concrete CMS (previously concrete 5) prior to version 8.5.7. Concrete CMS now checks to see if a file has a password in view_inline and, if it does, the file is not rendered.For version 8.5.6, the following mitigations were put in place a. restricting file types for view_inline to images only b. putting a warning in the file manager to advise users.Credit for discovery: "Solar Security Research Team"Concrete CMS security team CVSS scoring is 5.3: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:NThis fix is also in Concrete version 9.0.0

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-2021-22951 has been found in Concrete CMS.
Confidential information can be exposed externally.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Concrete CMS CVE-2021-22951" on the vendor's site.

CVE-2021-22951 (Concrete CMS)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
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 (unclassified) exists in Concrete CMS.

📍 Affected scope

Check the vendor advisory for the affected versions of Concrete CMS.

🔥 Severity

Severity: ?. Confidential information can be exposed externally.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

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

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで Concrete CMS を使っているサービスとバージョンを洗い出す。
2
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。

References

advisory documentation.concretecms.org
report hackerone.com