Central Authentication Service
CVE-2021-42567
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 6.1 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. |
| Exploit ScenarioDerived | A remote attacker could inject malicious scripts into web pages viewed by other users by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints. Rated medium severity (CVSS 6.1), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Cross-Site Scripting (XSS) vulnerability could allow attackers to inject malicious scripts into web pages viewed by other users.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Sanitize all user input, use Content-Security-Policy headers, encode output contextually (HTML, JS, URL). Use frameworks with built-in XSS protection.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in maven
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. Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints. Affected products include: Apereo Central Authentication Service. Version information: through 6.4.1.
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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:N/UI:R/S:C/C:L/I:L/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
Apereo CAS through 6.4.1 allows XSS via POST requests sent to the REST API endpoints.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
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.
Affected Products (CPE)NVD
The does not validate a parameter before making a request to it, which could allow unauthenticated users to perform SSRF
Multiple classes used within Apereo CAS before release 6.1.0-RC5 makes use of apache commons-lang3 RandomStringUtils for
Apereo Central Authentication Service (CAS) Server before 3.5.3 allows remote attackers to conduct LDAP injection attack
A vulnerability was found in Apereo CAS 6.6 and classified as problematic. Rated medium severity (CVSS 6.3), this vulner
Improper Authentication vulnerability in Apereo CAS in jakarta.servlet.http.HttpServletRequest.getRemoteAddr method allo
A vulnerability was found in Apereo CAS 6.6. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploitabl
A vulnerability has been found in Apereo CAS 6.6 and classified as problematic. Rated medium severity (CVSS 5.3), this v
Apereo CAS is an open source multilingual single sign-on solution for the web. Rated high severity (CVSS 7.5), this vuln
Apereo CAS 5.3.x before 5.3.16, 6.x before 6.1.7.2, 6.2.x before 6.2.4, and 6.3.x before 6.3.0-RC4 mishandles secret key
A vulnerability was found in Apereo CAS 5.2.6. Rated medium severity (CVSS 5.3), this vulnerability is remotely exploita
A vulnerability was found in Apereo CAS 5.2.6. Rated medium severity (CVSS 5.1), this vulnerability is remotely exploita
A vulnerability was found in Apereo CAS 5.2.6 and classified as critical. Rated low severity (CVSS 2.3), this vulnerabil
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