VulnTideExploited vulnerabilities, by vendor. Data as of 28 Oct 2026.
Known exploitedIn CISA's KEV catalog since 5 August 2026Ransomware use: known
JetBrains TeamCity

CVE-2026-63077: JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 5 Aug 2026, 9 days after the CVE record was published.

How likely is exploitation in the next 30 days?
93.6%

EPSS score, percentile 99.8 of all scored records

How severe?
9.8 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline 8 Aug 2026. Apply mitigations in accordance with vendor instructions … Full text

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • before 2026.1.3, 2025.11.7

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

What to do

Required action, set by CISA

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

CISA due date for this action: 8 August 2026.

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

JetBrains TeamCity
StatusVersions
Affectedbefore 2026.1.3, 2025.11.7

Versions not listed are: unaffected.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

About this vulnerability

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

Summary: CISA's KEV catalog, as of 28 Oct 2026.

  • CISA added CVE-2026-63077 to its Known Exploited Vulnerabilities (KEV) catalog on 5 Aug 2026.
  • CISA marks it as known to be used in ransomware campaigns.
  • The due date CISA sets for the required action is 8 Aug 2026.
  • The CVE record was published on 27 Jul 2026, 9 days before it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 9.8 (Critical), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 93.6% (percentile 99.8), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.

Description

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

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
27 Jul 2026CVE record published
5 Aug 2026Added to CISA KEV
8 Aug 2026CISA due date for the required action
23 Sep 2026CVE record last updated

References

More exploited JetBrains vulnerabilities

  • CVE-2024-27199: JetBrains TeamCity Relative Path Traversal Vulnerability (added 20 Apr 2026)
  • CVE-2024-27198: JetBrains TeamCity Authentication Bypass Vulnerability (added 7 Mar 2024)
  • CVE-2023-42793: JetBrains TeamCity Authentication Bypass Vulnerability (added 4 Oct 2023)