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CVE-2026-63077

JetBrains TeamCity Deserialization of Untrusted Data

9.8 CRITICALActively exploited (CISA KEV)Used in ransomwareEPSS 89.6%
  1. Published27 Jul 2026
  2. Added to CISA KEV5 Aug 2026
  3. Remediation due8 Aug 2026
Actively exploited (CISA KEV)

JetBrains TeamCity contains a deserialization of untrusted data vulnerability that could allow unauthenticated remote code execution via the agent polling protocol.

Added to KEV: 5 Aug 2026Federal remediation due: 8 Aug 2026Used in ransomware

Description

In JetBrains TeamCity before 2026.1.3, 2025.11.7 unauthenticated remote code execution was possible via the agent polling protocol

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

JetBrains Teamcity≥ 2026.1 < 2026.1.3 · < 2025.11.7

Remediation

Fixed in
JetBrains Teamcity≥ 2026.1.3

References

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Frequently asked

Is CVE-2026-63077 being actively exploited?

Yes. CVE-2026-63077 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 5 Aug 2026. It has been used in ransomware campaigns.

How severe is CVE-2026-63077?

CVE-2026-63077 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 89.6% probability of exploitation.

Which products are affected by CVE-2026-63077?

Affected products include JetBrains Teamcity.

How do I fix CVE-2026-63077?

Upgrade affected software to a fixed version, for example JetBrains Teamcity 2026.1.3 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-63077 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, a risk for it never ranks below high, and the update that fixes it moves to the Emergency patch lane. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.