Cross-Site Scripting (XSS) in Concrete CMS (CVE-2026-68534)
Summary
Cross-site scripting in Concrete CMS (CVE-2026-68534). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
Concrete CMS before 9.5.3 rendered Express entry labels as raw HTML when displaying associated entries, resulting in stored cross-site scripting. An unauthenticated attacker could submit a payload through a public Express Form; it then executed in an administrator's dashboard session when the associated entry was viewed, or in the browser of any visitor to a page using an Express Entry List block with association columns, allowing actions to be performed with that user's privileges. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 2.3 with vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks v01demort for reporting.
Source: NIST National Vulnerability Database NVD GitHub Advisory
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-2026-68534 has been found in Concrete CMS.
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 "Concrete CMS CVE-2026-68534" on the vendor's site.
CVE-2026-68534 (Concrete CMS) — CWE-79
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.
Cross-site scripting (XSS) (CWE-79) exists in Concrete CMS.
Check the vendor advisory for the affected versions of Concrete CMS.
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. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify 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。
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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。
References
- web documentation.concretecms.org
- web nvd.nist.gov
- web github.com