CVE-2021-29503 : Security Advisory and Response
Learn about CVE-2021-29503 affecting HedgeDoc before version 1.8.2. Explore the impact, technical details, and mitigation steps to protect against this cross-site scripting vulnerability.
HedgeDoc before version 1.8.2 is vulnerable to a cross-site scripting attack using the YAML-metadata of a note. An attacker with write access can embed HTML tags in the note, allowing injection of JavaScript, impacting confidentiality and integrity.
Understanding CVE-2021-29503
This CVE relates to an improper neutralization of script-related HTML tags in HedgeDoc notes.
What is CVE-2021-29503?
HedgeDoc, a platform for writing and sharing markdown, is affected by a cross-site scripting vulnerability in versions prior to 1.8.2. Attackers can inject malicious code into notes by manipulating metadata, potentially compromising data integrity and confidentiality.
The Impact of CVE-2021-29503
This vulnerability has a CVSS base score of 8.1, classified as high severity due to its potential for impacting confidentiality, integrity, and enabling unauthorized JavaScript injection.
Technical Details of CVE-2021-29503
The vulnerability allows attackers to execute cross-site scripting attacks by inserting HTML tags into note metadata. The issue is resolved in version 1.8.2.
Vulnerability Description
The improper handling of HTML metadata allows attackers to embed malicious scripts, affecting the rendering of notes on the frontend.
Affected Systems and Versions
HedgeDoc versions prior to 1.8.2 are affected by this vulnerability.
Exploitation Mechanism
An attacker with write access can exploit this flaw by injecting JavaScript via Open Graph metadata, impacting notes that allow guest edits.
Mitigation and Prevention
To address CVE-2021-29503, immediate action is essential to safeguard systems and data.
Immediate Steps to Take
Disable guest edits or restrict access until HedgeDoc is updated to version 1.8.2.
Long-Term Security Practices
Regularly update HedgeDoc to the latest versions to ensure protection against known vulnerabilities.
Patching and Updates
Ensure timely installation of patches and updates from HedgeDoc to mitigate the risk associated with this vulnerability.