SEPTEMBER 17, 2026
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Case File

CVE-2026-81903

HIGH · CVSS 7 EPSS 0.18%

Source: NVD + CISA KEV + EPSS · Published 2026-09-14 · Last synced 2026-09-17

CyberRota Analysis

AI-Generated

Concrete CMS versions 9.0.0 to 9.5.2 are vulnerable due to improper validation of user-submitted Page Container icon values, allowing an attacker with delegated access to inject malicious scripts into the dashboard. This vulnerability can lead to session token theft and unauthorized actions by other users, including administrators, who view the compromised dashboard. Organizations using affected versions should prioritize remediation to protect against potential exploitation and safeguard sensitive user sessions.

CVE
CVE-2026-81903
Severity
HIGH
CVSS
7
EPSS
0.18%

Original NVD Description

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.