Stored XSS Vulnerability in JetBrains IntelliJ IDEA Web Server
CVE-2026-123309

6.1MEDIUM

Key Information:

Vendor

Jetbrains
Status
Intellij Idea
Vendor
CVE Published:
6 November 2026

What is CVE-2026-123309?

In JetBrains IntelliJ IDEA prior to version 2026.3, a stored cross-site scripting (XSS) vulnerability exists in the built-in web server, allowing attackers to exploit Markdown previews. This flaw could potentially enable malicious scripts to be executed in users' browsers, posing significant security risks to applications leveraging this feature.

Affected Version(s)

IntelliJ IDEA 0 < 2026.3, 2026.2.4

References

https://www.jetbrains.com/privacy-security/issues-fixed/

CVSS V3.1

Score:
6.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.