CVE-2026-8197: Concrete5/concrete5 Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-h72c-xx3w-w8h7
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CWE-79
Published
Advisory Summary

CVE-2026-8197 is a HIGH cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Concrete5/concrete5 libraries in the Packagist ecosystem. The issue involves concrete cms is vulnerable to stored xss via oauth integration name. Remediation is available by upgrading affected packages to version 9.5.1.

CVE-2026-8197 at a Glance

CVE Identifier CVE-2026-8197
GHSA Identifier GHSA-h72c-xx3w-w8h7
Severity HIGH
CVSS v3.1 Base Score N/A
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Concrete5/concrete5
Package Ecosystem Packagist
Published Date
Last Updated

How to Fix CVE-2026-8197

To remediate this vulnerability, upgrade all affected Concrete5/concrete5 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

concrete5/concrete5 fixed: 9.5.1 
Upgrade concrete5/concrete5 to 9.5.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for concrete5/concrete5

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-8197, inspect your project dependencies for Concrete5/concrete5:

inspect dependencies for concrete5/concrete5

Analyze the terminal output to locate any version of Concrete5/concrete5 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 9.5.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Concrete5/concrete5, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via OAuth integration name. The OAuth authorize template renders the integration name (admin-controlled) through Concrete's t() translation helper as a sprintf-style format. The <strong>...</strong> wrap is built by PHP string interpolation before t() runs, so the integration name lands in the translated output as raw HTML. A rogue admin could potentially snoop on login submissions.The Concrete CMS security team thanks Yonatan Drori (Tenzai) for reporting this issue.

CVE-2026-8197 Affected Concrete5/concrete5 Versions

1 component(s)
Fixed Versions:
9.5.1
Product / Package Ecosystem Affected Versions Fixed Version
concrete5/concrete5
 Packagist
< 9.5.1
9.5.1

References

NVD — CVE-2026-8197 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-8197
documentation.concretecms.org/9-x/developers/intr... WEB
https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes
Concrete5/concrete5 Source Repository REPOSITORY
https://github.com/concretecms/concretecms

Frequently Asked Questions

What is CVE-2026-8197?
CVE-2026-8197 is a security vulnerability in Concrete5/concrete5 involving Concrete CMS is vulnerable to Stored XSS via OAuth integration name under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Concrete5/concrete5 versions are affected?
Affected versions include releases prior to 9.5.1 across affected packages: concrete5/concrete5.
What version fixes CVE-2026-8197?
Upgrading to 9.5.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is concrete5/concrete5 affected?
Yes, concrete5/concrete5 is affected in releases prior to 9.5.1. Upgrade your dependency to 9.5.1 or later.
What CWE is associated with CVE-2026-8197?
CVE-2026-8197 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Packagist dependencies for CVE-2026-8197?
Run the dependency tree command: 'inspect dependencies for concrete5/concrete5'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-h72c-xx3w-w8h7",
  "modified" : "2026-06-24T18:07:30Z",
  "published" : "2026-05-21T21:30:37Z",
  "aliases" : [ "CVE-2026-8197" ],
  "summary" : "Concrete CMS is vulnerable to Stored XSS via OAuth integration name",
  "details" : "Concrete CMS 9.5.0 and below is vulnerable to Stored XSS via OAuth integration name. The OAuth authorize template renders the integration name (admin-controlled) through Concrete's t() translation helper as a sprintf-style format. The <strong>...</strong> wrap is built by PHP string interpolation before t() runs, so the integration name lands in the translated output as raw HTML. A rogue admin could potentially snoop on login submissions.The Concrete CMS security team thanks Yonatan Drori (Tenzai) for reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Packagist",
      "name" : "concrete5/concrete5"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "9.5.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-8197"
  }, {
    "type" : "WEB",
    "url" : "https://documentation.concretecms.org/9-x/developers/introduction/version-history/951-release-notes"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/concretecms/concretecms"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-24T18:07:30Z",
    "nvd_published_at" : "2026-05-21T21:16:33Z"
  }
}