CVE-2026-63077

JetBrains TeamCity remote code execution, confirmed exploited in the wild.

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

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95%chance of exploitation in the next 30 days (EPSS), 99th percentile

5 Augadded to CISA's Known Exploited Vulnerabilities list, 2026

8 Augfederal remediation deadline, already passed

Passedpast the deadline: patch now

CISA's name for it	JetBrains TeamCity Deserialization of Untrusted Data Vulnerability
Vendor and product	JetBrains · TeamCity
Type	remote code execution · CWE-502
Exploited	Confirmed by CISA listed 5 August 2026
Likelihood	one of the most likely to be exploited of every vulnerability tracked
Deadline	8 August 2026 · already passed
Used in ransomware	Yes: CISA reports it used in ransomware campaigns
Advisories	blog.jetbrains.com ↗ · www.jetbrains.com ↗ · www.cisa.gov ↗ · www.cisa.gov ↗

What to do

Three steps, in this order

Step 1

Patch to the fixed version the vendor names, today if the product faces the internet.

Step 2

Until it is patched, take the affected service off the internet or put it behind a VPN or allow-list.

Step 3

Look for signs it was already used: new accounts, web shells, unexpected processes and outbound connections since the date it was listed.

CISA's required action	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's required action

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.

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Questions

CVE-2026-63077 in short

Is CVE-2026-63077 being exploited?

Yes. CISA added CVE-2026-63077 to its Known Exploited Vulnerabilities catalogue on 5 August 2026, which it does only on evidence of exploitation in the wild.

What is the CISA deadline for CVE-2026-63077?

US federal agencies must remediate it by 8 August 2026. Everyone else should treat that date as the latest safe point to patch an internet-facing system.

How likely is CVE-2026-63077 to be exploited in the next 30 days?

FIRST's Exploit Prediction Scoring System gives it 95%, the 99th percentile of every CVE it scores.

How do I fix CVE-2026-63077?

Patch to the fixed version the vendor names, today if the product faces the internet. Until it is patched, take the affected service off the internet or put it behind a VPN or allow-list. Look for signs it was already used: new accounts, web shells, unexpected processes and outbound connections since the date it was listed.

Same vendor

Other JetBrains vulnerabilities being exploited

CVE	Product	Type	Listed
CVE-2024-27199	TeamCity	path traversal	20 April 2026

Sources: CISA Known Exploited Vulnerabilities catalogue (released 10 November 2026) and FIRST EPSS. Page compiled automatically by SAK T.L.M, the threat-intelligence tool of SAK T.E.C, on 13 November 2026.