Xperience
CVE-2021-43991
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A05:2025 - Injection
ASVS 5.0
V1 - Encoding and Sanitization Output encoding, context-aware escaping
MITRE ATT&CK
2 techniques across 2 tactics: Initial Access, Execution The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 5.4 (MEDIUM). Attack characteristics: network attack vector, low complexity, low privileges required, user interaction required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. |
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Alert meAnalysisAI
The Kentico Xperience CMS version 13.0 - 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Rated medium severity (CVSS 5.4), this vulnerability is remotely exploitable, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Cross-Site Scripting (XSS) (CWE-79), which allows attackers to inject malicious scripts into web pages viewed by other users. The Kentico Xperience CMS version 13.0 - 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Persistent XSS vulnerabilities occur when the application stores and retrieves client supplied data without proper handling of dangerous content. This type of XSS vulnerability is exploited by submitting malicious script content to the application which is then retrieved and executed by other application users. The attacker could exploit this to conduct a range of attacks against users of the affected application such as session hijacking, account take over and accessing sensitive data. Affected products include: Kentico Xperience. Version information: version 13.0.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
The Kentico Xperience CMS version 13.0 - 13.0.43 is vulnerable to a persistent Cross-Site Scripting (XSS) vulnerability (also known as Stored or Second-Order XSS). Persistent XSS vulnerabilities occur when the application stores and retrieves client supplied data without proper handling of dangerous content. This type of XSS vulnerability is exploited by submitting malicious script content to the application which is then retrieved and executed by other application users. The attacker could exploit this to conduct a range of attacks against users of the affected application such as session hijacking, account take over and accessing sensitive data.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Cross-Site Scripting occurs when an application accepts untrusted data and sends it to a web browser without proper validation or encoding.
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)NVD
Kentico Xperience contains a second authentication bypass in the Staging Sync Server through None-type password handling
Kentico Xperience through 13.0.172 contains an authentication bypass in the Staging Sync Server through empty SHA1 usern
Remote code execution in Kentico Xperience CMS versions through 13.0.178 allows authenticated administrators to upload a
An issue was discovered in Kentico 12.0.x before 12.0.15, 11.0.x before 11.0.48, 10.0.x before 10.0.52, and 9.x versions
Kentico 9.0 through 11.0 has a stack-based buffer overflow via the SqlName, SqlPswd, Database, UserName, or Password fie
Kentico v10.0.42 allows Global Administrators to read the cleartext SMTP Password by navigating to the SMTP configuratio
Arbitrary code execution vulnerability in Kentico 9 through 11 allows remote authenticated users to execute arbitrary op
Kentico Xperience before 13.0.181 allows authenticated users to distribute malicious content (for stored XSS) via certai
The Kentico Xperience application does not fully validate or filter files uploaded via the multiple-file upload function
Kentico before 12.0.50 allows file uploads in which the Content-Type header is inconsistent with the file extension, lea
Kentico 11 through 12 lets attackers upload and explore files without authentication via the cmsmodules/medialibrary/for
An unsafe reflection vulnerability in Kentico Xperience allows an unauthenticated attacker to kill the current process,
GitHub PoC
Exploit-DB