Security readout for executives and security teams
Plain-English summary
A critical TeamCity flaw could let an unauthenticated remote attacker run code through the agent polling protocol. Successful compromise could expose source code, build secrets, software artifacts, and connected deployment systems. The supplied record identifies TeamCity releases before 2026.1.3 and 2025.11.7 as vulnerable, but its affected-version metadata is incomplete.
Executive priority
Treat as an emergency patching and exposure-reduction issue for affected TeamCity deployments. Prioritize externally reachable or high-trust CI/CD servers because compromise could affect proprietary code, credentials, build integrity, and downstream production environments. Escalate immediately if unusual activity is found.
Technical view
CVE-2026-63077 is a network-accessible, unauthenticated remote code execution vulnerability in TeamCity's agent polling protocol. It is categorized as CWE-502 and scored CVSS 3.1 9.8, with low complexity, no privileges, and no user interaction. The record indicates complete confidentiality, integrity, and availability impact.
Likely exposure
Organizations operating TeamCity versions preceding 2026.1.3 or 2025.11.7 may be exposed, depending on their release branch. Risk is greatest where the affected agent polling protocol is reachable from untrusted networks. The supplied affected-product metadata is inconsistent, so confirm applicability against JetBrains guidance.
Exploitation context
The supplied sources do not establish active exploitation, and this CVE is not listed as KEV in the bundle. Its unauthenticated network attack path and potential for full system impact make exploitation risk serious, but no public exploit availability or observed campaign should be inferred from this evidence.
Researcher notes
The record links RCE to the agent polling protocol and maps it to CWE-502, suggesting unsafe deserialization, but the supplied sources provide no implementation details. The affected array states version "0" with default unaffected, conflicting with the narrative version boundaries. Do not broaden affected versions without JetBrains confirmation.
Mitigation direction
- Upgrade to TeamCity 2026.1.3 or 2025.11.7, selecting the version appropriate for the deployed release branch.
- Confirm upgrade and compatibility requirements in JetBrains security guidance before production rollout.
- Restrict agent polling protocol access to trusted networks and authorized build infrastructure.
- Protect TeamCity administration and build systems from unnecessary internet exposure.
- Review and rotate sensitive build credentials if compromise indicators are discovered.
Validation and detection
- Inventory every TeamCity server and record its exact installed version and release branch.
- Confirm each instance runs 2026.1.3, 2025.11.7, or a later applicable release.
- Verify network controls prevent untrusted systems from reaching the agent polling protocol.
- Review TeamCity and surrounding system logs for unusual polling activity or unauthorized code execution.
- Validate build secrets, artifacts, and deployment integrations if suspicious activity is identified.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-502: Code execution behavior lookup
Code execution and unsafe deserialization weaknesses often justify reviewing execution behavior and process telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-63077 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H3.95.9JetBrainsVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://www.jetbrains.com/privacy-security/issues-fixed/CVE reference, JetBrains
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Deserialization of Untrusted Data
Deserialization of Untrusted Data represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.