Cross-site Scripting Vulnerability in Mattermost Server
Summary
CVE-2021-37860: Cross-site Scripting in Mattermost in github.com/mattermost/mattermost-server. Affected versions are not published. No fix is published. How to fix ↓
Also tracked for
The same CVE-2021-37860 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Mattermost Server is an open-source messaging platform that enables secure team collaboration. It is written in Go and provides features such as real-time messaging, file sharing, and integrations with other tools. The vulnerability affects the Mattermost Server codebase, specifically the github.com/mattermost/mattermost-server package.
Vulnerability Detail
The vulnerability in Mattermost Server is a Cross-site Scripting (XSS) issue. This type of vulnerability allows an attacker to inject malicious scripts into web pages viewed by other users. In the context of Mattermost Server, this could lead to the execution of arbitrary code or the theft of sensitive information. The vulnerability was identified in the github.com/mattermost/mattermost-server package and affects all versions prior to the fix in version 5.39.0.
How To Fix
No fixed version is published for this vulnerability.
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Workaround
If updating to the fixed version is not immediately feasible, a temporary workaround is to implement input validation and output encoding to mitigate the risk of XSS attacks. This can be achieved by using security libraries or frameworks that provide built-in protection against XSS vulnerabilities. Here is an example of input validation and output encoding in Go:
import (
"html"
"net/http"
)
func handleUserInput(w http.ResponseWriter, r *http.Request) {
userInput := r.FormValue("input")
sanitizedInput := html.EscapeString(userInput)
// Use sanitizedInput in the application
}
Conclusion
The Cross-site Scripting vulnerability in Mattermost Server poses a risk of arbitrary code execution and information theft. It is crucial to update to the fixed version and implement proper input validation and output encoding to mitigate the risk. Regular monitoring for security updates is also recommended.
See every vulnerability recorded for github.com/mattermost/mattermost-server →
FAQ
Cross-site Scripting (XSS) is a type of security vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users. This can lead to the execution of arbitrary code or the theft of sensitive information.
The Cross-site Scripting vulnerability in Mattermost Server can allow attackers to inject malicious scripts into the application, potentially leading to the execution of arbitrary code or the theft of sensitive information. This can impact the confidentiality, integrity, and availability of the system.
The vulnerability affects all versions of Mattermost Server prior to version 5.39.0. It is recommended to update to this version or later to mitigate the risk.
At the time of this report, there are no known public exploits for this vulnerability. However, it is important to address the vulnerability promptly to prevent potential exploitation.
The recommended mitigation measures include updating the Mattermost Server package to version 5.39.0 or later, implementing input validation and output encoding to prevent XSS attacks, and regularly monitoring for security updates and patches.
Related vulnerabilities
Recent vulnerabilities recorded for github.com/mattermost/mattermost-server.
