PatchTheCVECVE-2026-81899: Concrete CMS 9.0.0 to 9.5.2 stored group folder names without sanitization and printed them unescaped on the M
CVE-2026-81899 is a high-severity flaw (CVSS 7.3) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
Concrete CMS 9.0.0 to 9.5.2 stored group folder names without sanitization and printed them unescaped on the Members > Groups dashboard page, resulting in stored cross-site scripting. The add and edit group-folder handlers stored the submitted folder name without neutralizing HTML, and the group search grid returned it without output encoding, so the Groups dashboard rendered the name as live markup. An authenticated user holding the Add Group Fo
Why this priority
- High severity
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 7.3 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | High |
| User interaction | Passive |
| EPSS exploit chance | 0.5% (top 59%) |
| CISA exploited list | No |
| Weakness | CWE-79 |
| Published | 2026-09-15 |
| Last modified | 2026-09-16 |
Last updated 2026-09-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-81899?
No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.
Is CVE-2026-81899 being exploited?
CVE-2026-81899 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-81899 affect?
CVE-2026-81899 affects affected software. Severity is high (CVSS 7.3). Concrete CMS 9.0.0 to 9.5.2 stored group folder names without sanitization and printed them unescaped on the Members > Groups dashboard page, resulting in stored cross-site scripting. The add and edit group-folder handlers stored the submit
How urgent is CVE-2026-81899?
Priority 36/100. High severity