CVE-2021-43856
8.2 · HIGHOverview
CVE-2021-43856 is a high-severity vulnerability affecting requarks wiki.js. It was published on December 27, 2021 and has a CVSS 3.1 base score of 8.2 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.2, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
Wiki.js is a wiki app built on Node.js. Wiki.js 2.5.263 and earlier is vulnerable to stored cross-site scripting through non-image file uploads for file types that can be viewed directly inline in the browser. By creating a malicious file which can execute inline JS when viewed in the browser (e.g. XML files), a malicious Wiki.js user may stage a stored cross-site scripting attack. This allows the attacker to execute malicious JavaScript when the file is viewed directly by other users. The file must be opened directly by the user and will not trigger directly in a normal Wiki.js page. A patch in version 2.5.264 fixes this vulnerability by adding an optional (enabled by default) force download flag to all non-image file types, preventing the file from being viewed inline in the browser. As a workaround, disable file upload for all non-trusted users. --- Thanks to @Haxatron for reporting this vulnerability. Initially reported via https://huntr.dev/bounties/266bff09-00d9-43ca-a4bb-bb54064
Remediation
Check the references section for vendor advisories and patches from requarks. Update wiki.js to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| requarks | wiki.js | >= 0, < 2.5.264 | Affected |
References
Frequently Asked Questions
What is CVE-2021-43856?
CVE-2021-43856 is a high-severity vulnerability affecting requarks wiki.js. It was published on December 27, 2021 and has a CVSS 3.1 base score of 8.2 (HIGH).
How severe is CVE-2021-43856?
This vulnerability has a CVSS 3.1 base score of 8.2, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2021-43856?
Check the references section for vendor advisories and patches from requarks. Update wiki.js to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2021-43856?
CyberStrike's AI-powered security agents can automatically detect CVE-2021-43856 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
Automated penetration testing that runs continuously, not just quarterly.
AI-driven PR review catches vulnerable dependencies before they ship.
Browser-based exploitation validates findings with real proof-of-concept.
Related HIGH CVEs from 2021
View all →systeminformation is an open source system and OS information library for node.js. A command injecti
An Improper Access Control Privilege Escalation Vulnerability was discovered in the User Setting of
An SQL injection Privilege Escalation Vulnerability was discovered in the Orion Platform reported by
Insecure deserialization leading to Remote Code Execution was detected in the Orion Platform version
Insecure Deserialization of untrusted data remote code execution vulnerability was discovered in Pat
Deserialization of Untrusted Data in the Web Console Chart Endpoint can lead to remote code executio
Insecure Deseralization of untrusted data remote code execution vulnerability was discovered in Patc
SAP Web Dispatcher versions - 7.49, 7.53, 7.77, 7.81, KRNL64NUC - 7.22, 7.22EXT, 7.49, KRNL64UC -7.2
uploader.php in the KCFinder integration project through 2018-06-01 for Drupal mishandles validation
An issue was discovered in the PageLayer plugin before 1.1.2 for WordPress. The pagelayer_settings_p
MK-AUTH through 19.01 K4.9 allows CSRF for password changes via the central/executar_central.php?aca
IBM Cloud Pak System 2.3 is vulnerable to cross-site request forgery which could allow an attacker t