Cyber Resilience

CVE-2026-49376

Access Control in Jetbrains Teamcity ≤ 2026.1

Access Control
Published
29 May 2026
Modified
22 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 6.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
EPSS Score 0.0022 12th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-49376 is a medium-severity Incorrect Authorization (CWE-863) vulnerability in Jetbrains Teamcity. Its CVSS base score is 6.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Valid Accounts (T1078); ranked at the 12th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

In JetBrains TeamCity before 2026.1 insufficient username validation in the SAML plugin

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1550 Use Alternate Authentication Material Lateral Movement
Adversaries may use alternate authentication material, such as password hashes, Kerberos tickets, and application access tokens, in order to move laterally within an environment and bypass normal system access controls.
attack.mitre.org →
Why these techniques?

Insufficient SAML username validation enables abuse of valid accounts and alternate authentication material via SSO impersonation.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2024-36364Same product: Jetbrains Teamcity
CVE-2024-56350Same product: Jetbrains Teamcity
CVE-2025-24460Same product: Jetbrains Teamcity
CVE-2025-54533Same product: Jetbrains Teamcity
CVE-2023-34218Same product: Jetbrains Teamcity
CVE-2024-36376Same product: Jetbrains Teamcity
CVE-2024-28174Same product: Jetbrains Teamcity
CVE-2025-67740Same product: Jetbrains Teamcity
CVE-2024-36365Same product: Jetbrains Teamcity
CVE-2024-56348Same product: Jetbrains Teamcity

Affected Assets

jetbrains
teamcity
≤ 2026.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • AC-3 Access Enforcement
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match
prevent

Directly requires validation of input data (usernames) to prevent malformed or unauthorized values from being accepted during SAML processing.

AC-3 Access Enforcement good match
prevent

Enforces access control decisions based on validated identities, blocking the incorrect authorization (CWE-863) that results from weak SAML username checks.

AC-6 Least Privilege partial match
prevent

Limits privileges granted after SAML authentication, reducing the impact of any authorization bypass caused by insufficient username validation.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

A.5.18 Access rights partial match
prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.3 Information access restriction partial match
prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

References