CVE-2025-8571
Concrete CMS 9 through 9.4.2 and below 8.5.21 is vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- High
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
Concrete CMS 9 through 9.4.2 and below 8.5.21 is vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
- Record
CVE-2025-8571- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2025-23658
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
- Record
EUVD-2025-23658- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-4pcg-pjp5-3mc6
Concrete CMS vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions.
- Record
GHSA-4pcg-pjp5-3mc6- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-20, CWE-79
- Updated
- 2026-11-02
NVD
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
- Record
CVE-2025-8571- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 4.8 Medium
CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N - Weakness
- CWE-20, CWE-79
- Updated
- 2026-11-02
OSV
Concrete CMS 9 through 9.4.2 and below 8.5.21 is vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 4.8 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N. Thanks Fortbridge https://fortbridge.co.uk/ for performing a penetration test and vulnerability assessment on Concrete CMS and reporting this issue.
- Record
CVE-2025-8571- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-20
- Updated
- 2026-11-02
OSVGHSA-4pcg-pjp5-3mc6
Concrete CMS vulnerable to Reflected Cross-Site Scripting (XSS) in Conversation Messages Dashboard Page
Concrete CMS 9 to 9.4.2 and versions below 8.5.21 are vulnerable to Reflected Cross-Site Scripting (XSS) in the Conversation Messages Dashboard Page. Unsanitized input could cause theft of session cookies or tokens, defacement of web content, redirection to malicious sites, and (if victim is an admin), the execution of unauthorized actions.
- Record
GHSA-4pcg-pjp5-3mc6- CVSS 4.0
- 4.8 Medium
CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-20, CWE-79
- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
concrete5/concrete5Packagist |
before 8.5.21 | 8.5.21 |
concrete5/concrete5Packagist |
9.0.0RC1 up to 9.4.3 | 9.4.3 |
concrete5/concrete5Packagist |
before 8.5.21, plus listed versions 8.08.0.18.0.28.0.38.1.0 Show 38 moreShow less8.2.08.2.0RC28.2.18.3.08.3.18.3.28.4.08.4.0RC38.4.0RC48.4.18.4.28.4.38.4.48.4.58.5.08.5.0RC18.5.0RC28.5.18.5.108.5.118.5.128.5.138.5.148.5.158.5.168.5.178.5.188.5.198.5.28.5.208.5.38.5.48.5.58.5.68.5.6RC18.5.78.5.88.5.9 |
8.5.21 |
concrete5/concrete5Packagist |
9.0.0RC1 up to 9.4.3, plus listed versions 9.0.09.0.0RC39.0.0RC49.0.19.0.2 Show 30 moreShow less9.1.09.1.19.1.29.1.39.2.09.2.0RC29.2.19.2.29.2.39.2.49.2.59.2.69.2.79.2.89.2.99.3.09.3.19.3.29.3.39.3.49.3.59.3.69.3.79.3.89.3.99.4.09.4.0RC19.4.0RC29.4.19.4.2 |
9.4.3 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | chimdi2700/CVE-2025-8571 | 2025-09-12 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-8571 is a medium vulnerability (CVSS 4.8) in Concrete Cms Cms, published August 5, 2025. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 32nd percentile. Fixed in concrete5/concrete5 8.5.21.
References
documentation.concretecms.org/developers/introduction/version-history/8521-release-notes
concretecms.org/download
nvd.nist.gov/vuln/detail/CVE-2025-8571
github.com/concretecms/concretecms/commit/4b39dcc17c309dc82eb8398e8cdb146942f62f92