dbcve.org
YoutrackApplication · Jetbrains

CVE-2021-31903

MEDIUM · 6.1 CVSS v3.1 Published 2021-05-11
Fix available
A fix is available. Upgrade to 2021.1.9819 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In JetBrains YouTrack before 2021.1.9819, a pull request's title was sanitized insufficiently, leading to XSS.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In JetBrains YouTrack before version 2021.1.9819, the pull request title field was not properly sanitized, allowing attackers to inject malicious JavaScript code through the title that would execute in the context of other users' browsers when viewing the pull request.

MitigationUpgrade YouTrack to version 2021.1.9819 or later which includes proper sanitization of pull request titles.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
YoutrackApplication
Affected:< 2021.1.9819

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check YouTrack version
    Access the YouTrack administration interface or check the product version information. In the web UI, this is typically found in the 'About' section under 'Administration' > 'Diagnostics', or by examining the installation manifest files.
    Affected if The installed version is below 2021.1.9819 (any version from the initial release up to 2021.1.9818 is vulnerable)
  2. Verify pull request integration is enabled
    Check if any Git integration (GitHub, GitLab, Bitbucket, or other Git hosting) with pull request tracking is configured in YouTrack. Navigate to 'Administration' > 'Integrations' and look for active repository connections that include pull request features.
    Affected if Pull request integration is enabled and connected to external Git repositories
  3. Inspect pull request titles in the system
    Review existing pull requests linked to YouTrack issues. In the YouTrack UI, search for issues with attached pull requests and examine the PR title fields for any suspicious content such as <script> tags, javascript: handlers, or other HTML/JS injection patterns.
    Affected if Any pull request titles contain unsanitized HTML or JavaScript code that could execute in user browsers

You are affected if your YouTrack version is earlier than 2021.1.9819 AND you have pull request integration enabled with external Git repositories.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to 2021.1.9819 or later
Fixed in 2021.1.9819
Interim mitigation

Upgrade YouTrack to version 2021.1.9819 or later which includes proper sanitization of pull request titles.

Fix this in Youtrack Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-31903 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data