CVE-2026-59795
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 · uneditedIn JetBrains TeamCity before 2026.1.2 stored XSS via unauthenticated agent registration was possible
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 · moderate confidenceA stored cross-site scripting (XSS) vulnerability exists in JetBrains TeamCity's unauthenticated agent registration functionality. Attackers can inject malicious JavaScript code through the agent registration process, which gets stored in the system and executed when administrative users view the agent information.
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< 2026.1.2CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Identify TeamCity versionAccess the TeamCity Administration > Server Administration page, or check the <TeamCity data directory>/config/internal.properties file for the version numberAffected if Installed version is below 2026.1.2
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Verify agent registration is accessibleNavigate to Administration > Agent Management > Agents and check if the agent registration functionality is enabled and accessible to unauthenticated usersAffected if Agent registration is enabled and reachable without authentication
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Check unauthenticated agent registration settingReview the Server Configuration settings under Administration > Server Administration > Agent Settings to confirm if unauthenticated agent registration is permittedAffected if Unauthenticated agent registration is allowed in the TeamCity configuration
You are affected if your TeamCity installation version is below 2026.1.2 and unauthenticated agent registration is enabled, allowing an attacker to inject malicious JavaScript through the agent registration endpoint.
Generated from the published advisory. Verify against your own configuration.
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.
dbcve · scoped2026.1.2
Upgrade TeamCity to version 2026.1.2 or later to apply the security patch for this stored XSS vulnerability.
2026.1.2
- 1. Back up your TeamCity server data, including the <TeamCity home>/data directory and database.
- 2. Review the TeamCity 2026.1.2 release notes at www.jetbrains.com for any pre-upgrade requirements.
- 3. Stop the TeamCity server and all related services.
- 4. Download TeamCity 2026.1.2 from the official JetBrains website (www.jetbrains.com/teamcity/download).
- 5. Install the new version following the standard TeamCity upgrade instructions.
- 6. Start the TeamCity server and verify all services are running correctly.
- 7. Test that agent registration functionality works properly and the XSS vulnerability is remediated.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-59795 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-59795 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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
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