CVE-2026-63373
Received Received - Intake

OAuth State Validation Bypass in draw.io

Publication date: 2026-09-21

Last updated on: 2026-09-21

Assigner: GitHub, Inc.

Description
draw.io is a configurable diagramming and whiteboarding application. Prior to version 30.2.7, the OAuth callback handler in src/main/java/com/mxgraph/online/AbsAuth.java skips comparison of stateToken and cookieToken whenever IS_GAE is false, which affects self-hosted Docker and WAR deployments. An attacker can provide an authorization code for the attacker's cloud-storage identity and induce a victim to visit a callback URL, causing the victim's draw.io session to become authenticated as the attacker identity without a valid state binding. The shared handler affects Google Drive, OneDrive, GitHub, GitLab, and Dropbox integrations. The victim can then unknowingly perform cloud-storage actions under the attacker's identity, causing session integrity loss and misattribution, but the identity binding does not itself grant access to existing victim cloud files. This issue is fixed in version 30.2.7.

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Meta Information

Published
2026-09-21
Last Modified
2026-09-21
Generated
2026-09-21
AI Q&A
2026-09-21
EPSS Evaluated
N/A
NVD
CVE-2026-63373
EUVD
EUVD-2026-84008

Affected Vendors & Products

Showing 7 associated CPEs
Vendor Product Version / Range
jgraph draw.io 30.2.7
draw.io draw.io 30.2.7
google drive *
onedrive onedrive *
github github *
gitlab gitlab *
dropbox dropbox *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-352 The web application does not, or cannot, sufficiently verify whether a request was intentionally provided by the user who sent the request, which could have originated from an unauthorized actor.

Attack-Flow Graph

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Executive Summary

CVE-2026-63373 is a CSRF vulnerability in draw.io's OAuth callback handling for self-hosted deployments. The state token validation, which prevents OAuth code injection, is skipped when the server is not running on Google App Engine (GAE). This affects Docker and WAR deployments and allows an attacker to inject their OAuth code into a victim's session.

Detection Guidance

Check draw.io version in use. If running self-hosted Docker or WAR deployments below 30.2.7, the system is vulnerable. Review OAuth callback logs for unexpected state token mismatches or unauthorized cloud-storage authentications.

Impact Analysis

An attacker can trick you into clicking a malicious link. This hijacks your draw.io session, binding it to the attacker's cloud-storage identity (Google Drive, OneDrive, GitHub, GitLab, or Dropbox). The attacker gains read/write access to your files through draw.io without you realizing your session is compromised.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles and HIPAA's security requirements. It risks data integrity and confidentiality, potentially causing compliance breaches if exploited.

Mitigation Strategies

Upgrade draw.io to version 30.2.7 or later. Ensure state token validation is enforced in all OAuth callback handlers. Review and revoke any suspicious cloud-storage sessions linked to draw.io integrations.

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