Vulnerability in Contao (CVE-2021-35210)
Summary
Vulnerability in Contao (CVE-2021-35210). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Impact
It is possible to inject code into the tl_log table that will be executed in the browser when the system log is called in the back end.
Patches
Update to Contao 4.9.16 or 4.11.5.
Workarounds
Disable the system log module in the back end for all users (especially admin users).
References
https://contao.org/en/security-advisories/cross-site-scripting-in-the-system-log-2021
For more information
If you have any questions or comments about this advisory, open an issue in contao/contao.
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-2021-35210 has been found in Contao.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Contao CVE-2021-35210" on the vendor's site.
CVE-2021-35210 (Contao)
Attack vector: remote (network-reachable) / unauthenticated
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.
A vulnerability (unclassified) exists in Contao.
Check the vendor advisory for the affected versions of Contao.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Contao' . 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
-
1Identify exposure identify
grep -r 'Contao' . | 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
Contaoを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-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
References
- advisory nvd.nist.gov
- package github.com
- web contao.org
- web github.com
- web github.com
- web github.com