CVE-2026-81903 Details
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.
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Exploit prediction scoring system (EPSS) score for CVE-2026-81903
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
0.21 Probability of exploitation activity being observed over the next 30 days (11th percentile)
CVSS score for CVE-2026-81903
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
5.4 Medium
Products affected by CVE-2026-81903
ConcreteCMS 9.2.8
ConcreteCMS 9.2.9
ConcreteCMS 9.3.2
ConcreteCMS 9.3.7
ConcreteCMS 9.3.8
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Low
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CVE-2026-81903 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
US 100 60.61%
DE 22 13.33%
JP 12 7.27%
GB 6 3.64%
NL 6 3.64%
TR 5 3.03%
IE 3 1.82%
PL 3 1.82%
AT 2 1.21%
FR 2 1.21%

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CVE-2026-81903 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Technology 149 93.13%
Telecommunications 4 2.50%
Education 3 1.88%
Business Services 2 1.25%
Finance 1 0.63%
Government/Politics 1 0.63%

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