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Full vulnerability report · 2026
CVE-2026-63077High confidence

JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

JetBrains · TeamCity

9.8CriticalCVSS 3.1
Recommended action
Mitigate now

CISA confirms exploitation in the wild and lists 2026-08-08 as the remediation due date.

Mitigation available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 89.57% for the current model date.

Compensating controls

  • Apply the linked authoritative mitigation while planning the permanent fix.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs JetBrains TeamCity and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-49369

CISA KEV mirrored by ENISA

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

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 5 Aug 2026. Evidence sources: cisa_kev.
ENISA score
9.8 · CVSS 3.1
Advisory evidence
1 linked advisory record
Recommended actionMitigate now

CISA confirms exploitation in the wild and lists 2026-08-08 as the remediation due date.

Mitigation available
01

What, why and how

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

What

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

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

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

Why

Attacker-influenced serialised data is reconstructed as trusted objects, which can invoke dangerous application behaviour.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-08-05. Known ransomware campaign use is recorded.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Deserialization of Untrusted Data → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-502 ↗

CWE-502: Deserialization of Untrusted Data. The product deserializes untrusted data without sufficiently ensuring that the resulting data will be valid.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CHighConfidentiality impact: A successful attack can cause a major loss.IHighIntegrity impact: A successful attack can cause a major loss.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-502CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-49369Known-exploited evidence recorded

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

Official EUVD record ↗
BSI · German · WID-SEC-2026-2534JetBrains TeamCity: Schwachstelle ermöglicht Codeausführung

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in JetBrains TeamCity ausnutzen, um beliebigen Programmcode auszuführen.

Official advisory ↗
Canadian Centre for Cyber Security · English · AV26-752JetBrains security advisory (AV26-752) – Update 1

As of July 27, 2026, JetBrains is affected by a vulnerability in the following product: On August 5, 2026, Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-63077 to their Known Exploited Vulnerabilities (KEV) Database.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260729Security Bulletin 29 Jul 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 29 Jul 2026, published on 29 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CSIRT Italia · Italian · rilevata-vulnerabilita-in-jetbrains-teamcityRilevata vulnerabilità in JetBrains TeamCity

Rilasciato aggiornamento per risolvere una vulnerabilità di sicurezza con gravità “critica” in JetBrains TeamCity. Tale vulnerabilità, qualora sfruttata, consentirebbe ad un attaccante remoto di eseguire codice arbitrario sui sistemi interessati, eludendo i meccanismi di autenticazione.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-026991JetBrainsのTeamCityにおける信頼できないデータのデシリアライゼーションに関する脆弱性

JetBrains TeamCity のバージョン 2026.1.3 および 2025.11.7 より前のバージョンでは、エージェントポーリングプロトコルを介して認証されていない状態でリモートコード実行が可能でした。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6909JetBrains 제품 보안 업데이트 권고

JetBrains TeamCity 에서 발생하는 Deserialization of Untrusted Data 취약점(CVE-2026-63077) [1][2]

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6900美 CISA 발표 주요 Exploit 정보공유(Update. 2026-08-05)

JetBrains TeamCity Deserialization of Untrusted Data Vulnerability

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Mitigation available
Affected
TeamCity: < 2026.1.3, 2025.11.7
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
The Cyber Centre encourages users and administrators to review the provided web links and apply any necessary updates as they become available.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 27 Jul 2026 · Last source change 23 Sept 2026, 03:55 UTC · CWE-502 · Deserialization of Untrusted Data

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-49369
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. CISA KEV stateCISA KEV now confirms exploitation in the wild.
    Before
    listed in CISA KEV since 2026-08-05
    After
    listed in CISA KEV since 2026-08-05
    CISA KEV ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: cyber.gc.ca/jetbrains-security-advisory-av26-752.
    Before
    remediation: cyber.gc.ca/jetbrains-security-advisory-av26-752 · vendor advisory: jetbrains.com/issues-fixed
    After
    vendor advisory: jetbrains.com/issues-fixed
    cve@jetbrains.com ↗
  3. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    cve@jetbrains.com ↗
  4. BlackTree coverageBlackTree article coverage changed from 1 BlackTree article to 1 BlackTree article.
    Before
    1 BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  5. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  6. Vendor guidanceAuthoritative vendor guidance changed: removed remediation: cyber.gc.ca/jetbrains-security-advisory-av26-752.
    Before
    remediation: cyber.gc.ca/jetbrains-security-advisory-av26-752 · vendor advisory: jetbrains.com/issues-fixed
    After
    vendor advisory: jetbrains.com/issues-fixed
    cve@jetbrains.com ↗
  7. Remediation statusRemediation status changed from Mitigation available to Awaiting fix.
    Before
    Mitigation available
    After
    Awaiting fix
    cve@jetbrains.com ↗
  8. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 2026.1.3, 2025.11.7 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    TeamCity: < 2026.1.3, 2025.11.7 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
  9. Remediation statusRemediation status changed from Awaiting fix to Mitigation available.
    Before
    Awaiting fix
    After
    Mitigation available
    Canadian Centre for Cyber Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Remediation guidance recorded
ENISA EUVD · EUVD-2026-49369↗Canadian Centre for Cyber Security remediation guidance↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-63077 · cve.blacktree.nl