PatchSiren cyber security CVE debrief

CVE-2026-49383 JetBrains CVE debrief

A low-severity XML External Entity (XXE) vulnerability exists in JetBrains IntelliJ IDEA versions prior to 2026.1. The flaw resides in the UI Designer form parser, which processes XML-based form definitions. Successful exploitation could allow information disclosure through local file access when a user opens a maliciously crafted form file. The attack requires local access and user interaction, with no privileges needed. The CVSS 3.1 score of 3.3 reflects the limited impact scope and high user interaction requirement. JetBrains has addressed this issue in version 2026.1.

Vendor: JetBrains
Product: IntelliJ IDEA
CVSS: LOW 3.3
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-05-29
Original CVE updated: 2026-05-29
Advisory published: 2026-05-29
Advisory updated: 2026-05-29

Who should care

Development teams using JetBrains IntelliJ IDEA for Java application development, particularly those working with Swing UI Designer forms. Security teams managing IDE deployments and software supply chain integrity.

Technical summary

The UI Designer form parser in IntelliJ IDEA before 2026.1 fails to properly restrict XML external entity references when processing form definition files. This XXE vulnerability (CWE-611) could enable local information disclosure through crafted XML form files. The attack vector is local with required user interaction, resulting in low confidentiality impact and no integrity or availability impact.

Defensive priority

routine

Recommended defensive actions

Upgrade JetBrains IntelliJ IDEA to version 2026.1 or later
Review and validate UI Designer form files from untrusted sources before opening
Consider disabling automatic form file processing for files from external origins
Monitor JetBrains security advisories for additional guidance

Evidence notes

CVE published 2026-05-29. NVD status: Undergoing Analysis. CWE-611 (Improper Restriction of XML External Entity Reference) identified. Vendor advisory confirms fix in 2026.1.

Official resources

2026-05-29