CVE-2026-63077Known exploitationNetwork attack vectorHinoki check available

Unauthenticated command execution via agent polling deserialization

Published Jul 27, 2026 · Updated Jul 27, 2026

Deserialization in JetBrains TeamCity On-Premises allows remote attackers to execute OS commands through HTTP(S) agent polling. The agent polling handler deserializes attacker-controlled protocol data before authentication, allowing unsafe object construction to reach command execution. Any unauthenticated user with HTTP(S) access can run commands with the TeamCity server process's privileges, exposing stored credentials, server state, build artifacts, and downstream pipelines.

CVSS severity9.8
Critical
EPSS probability86.52%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Deserialization in JetBrains TeamCity On-Premises allows remote attackers to execute OS commands through HTTP(S) agent polling. The agent polling handler deserializes attacker-controlled protocol data before authentication, allowing unsafe object construction to reach command execution. Any unauthenticated user with HTTP(S) access can run commands with the TeamCity server process's privileges, exposing stored credentials, server state, build artifacts, and downstream pipelines.

The record

CVE
CVE-2026-63077
Published
Jul 27, 2026
Updated
Jul 27, 2026
Vendor
JetBrains
Product
TeamCity On-Premises
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <2026.1.3, 2025.11.7

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

JetBrains · TeamCity On-Premisesversion=0 <2026.1.3, 2025.11.7

Published CVSS scores

9.8JetBrains s.r.o.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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Reported exploitation

Technologies

Your stack

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Your stack

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