EUVD-2026-78076
GHSA-6338-gx7c-fcjj
Severity by source
CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/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
Web application network-accessible (AV:N); attacker needs delegated low-privilege account (PR:L); victim must view the page (UI:R); session hijack crosses user boundary (S:C); no direct availability impact.
Primary rating from Vendor (ConcreteCMS).
CVSS VectorVendor: ConcreteCMS
Lifecycle Timeline
2DescriptionCVE.org
Concrete CMS versions 9.0.0 to 9.5.2 stored the Page Container icon value submitted through the dashboard without validating it against the set of known container icons. The unvalidated value was later concatenated into the src attribute of an img tag by a helper that did not encode attribute output, and was rendered raw in the Containers dashboard list and editor views. A user with delegated access to the Page Containers dashboard could store a crafted icon value that broke out of the src attribute and executed script in the authenticated session of another editor or administrator who viewed the list, enabling session token theft and privileged dashboard actions. The Concrete CMS security team gave this vulnerability a CVSS v4.0 score of 7.0 with vector CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N. Thanks Andrew Gonzalez for reporting.
AnalysisAI
Stored XSS in Concrete CMS 9.0.0-9.5.2 allows a low-privileged user with delegated access to the Page Containers dashboard to inject malicious script via a crafted container icon value that breaks out of an img src attribute due to missing output encoding. The payload persists in the database and executes in the authenticated session of any administrator or editor who subsequently views the Containers dashboard list or editor views, enabling session token theft and unauthorized privileged CMS actions. …
Unlock full vulnerability intelligence
- Risk assessment & exploitation conditions
- Attack chain visualization
- Remediation with exact patch versions
- Threat intelligence from 22 sources
- Personal watchlist & email alerts
Free forever · No credit card required
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires an authenticated Concrete CMS dashboard account with delegated access specifically to the Page Containers section - this permission is not granted by default and must be explicitly assigned by an administrator. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The vendor's CVSS 4.0 score of 7.0 (CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N) correctly captures the high privilege prerequisite (PR:H) and the requirement for passive victim interaction (UI:P), which significantly narrow the attacker population compared to unauthenticated web vulnerabilities. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade to Concrete CMS 9.5.3 or later, which introduces validation of the Page Container icon value against the permitted set of known icons at submission time and adds proper attribute-context output encoding in the rendering helper. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, identify all Concrete CMS deployments and confirm whether versions 9.0.0-9.5.2 are in use. …
Sign in for detailed remediation steps and compensating controls.
Threat intelligence, references, and detailed analysis are available after sign-in.
More in Concrete Cms
View allA bypass of adding remote files in Concrete CMS (previously concrete5) File Manager leads to remote code execution in Co
Concrete5 through 8.5.5 deserializes Untrusted Data. Rated high severity (CVSS 7.2), this vulnerability is remotely expl
Concrete5 up to and including 8.5.2 allows Unrestricted Upload of File with Dangerous Type such as a .php file via File
Concrete5 before 8.5.3 allows Unrestricted Upload of File with Dangerous Type such as a .phar file. Rated high severity
A Server Side Request Forgery (SSRF) vulnerability in tools/files/importers/remote.php in concrete5 8.2.0 can lead to at
Unauthenticated file usage disclosure in Concrete CMS 9.5.0 and below exposes internal page structure to any network-acc
concrete5 8.1.0 places incorrect trust in the HTTP Host header during caching, if the administrator did not define a "ca
Concrete CMS versions below 9.4.8 contain a cross-site request forgery vulnerability in the Anti-Spam Allowlist Group Co
concrete5 8.1.0 has CSRF in Thumbnail Editor in the File Manager, which allows remote attackers to disable the entire in
Unauthenticated information disclosure in Concrete CMS 9.5.0 and earlier allows remote attackers to enumerate all conver
Unauthenticated information disclosure in Concrete CMS 9.5.0 and below allows any network-accessible attacker to enumera
Concrete CMS before 8.5.13 and 9.x before 9.2.2 allows unauthorized access because directories can be created with insec
Same weakness CWE-79 – Cross-site Scripting (XSS)
View allShare
External POC / Exploit Code
Leaving vuln.today