CVE-2026-86486

Received Received - Intake

JetBrains YouTrack Blank VCS Webhook Handler Bypass

Publication date: 2026-09-07

Last updated on: 2026-09-08

Assigner: JetBrains s.r.o.

Description

In JetBrains YouTrack before 2026.2.18634 the generic VCS webhook handler failed open when its secret was blank

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-09-07

Last Modified

2026-09-08

Generated

2026-09-27

AI Q&A

2026-09-07

EPSS Evaluated

2026-09-26

NVD

CVE-2026-86486

EUVD

EUVD-2026-72502

Affected Vendors & Products

Vendor	Product	Version / Range
jetbrains	youtrack	to 2026.2.18634 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-306	The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

Executive Summary

In JetBrains YouTrack before version 2026.2.18634, there is a vulnerability where the generic VCS webhook handler fails to properly validate requests when its secret is left blank. This means an attacker could potentially send malicious webhook payloads without needing to know the secret, leading to unauthorized actions being triggered.

Detection Guidance

To detect this vulnerability, check if JetBrains YouTrack instances have blank VCS webhook secrets. Inspect webhook configurations for missing or empty secret values. Verify logs for unauthorized VCS webhook requests. Ensure all webhooks have non-empty secrets configured.

Impact Analysis

This vulnerability could allow unauthorized users to trigger webhook actions in your YouTrack instance if the VCS webhook secret is blank. This might lead to unintended changes, data leaks, or service disruptions depending on how webhooks are configured in your system.

Compliance Impact

The vulnerability allows unauthorized access to webhook functionality due to improper secret validation, which could lead to data exposure or integrity issues. This may violate compliance requirements under GDPR (data protection) and HIPAA (health data security) by enabling unauthorized data access or modification.

Mitigation Strategies

Update JetBrains YouTrack to version 2026.2.18634 or later to address the vulnerability. Ensure VCS webhook secrets are properly configured and not left blank.

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