Junglewise Threat Intelligence

CVE-2026-41839: VMware Spring Framework session fixation in WebFlux

CVE-2026-41839 · Severity: medium · CVSS 4.2 · Published 2026-06-09

Technologies: VMware Spring Framework. Vendors: VMware.

Executive brief

Spring Framework is a widely used software framework for building Java-based web applications. A vulnerability in its WebFlux component could allow an attacker who has compromised a subdomain (for example, through a separate web attack) to hijack the session of a legitimate authenticated user. This could lead to unauthorized access to user accounts and sensitive data within the application.

Technical details

A session fixation vulnerability (CWE-384) exists in Spring Framework's WebFlux module. The flaw allows an attacker who has control over a subdomain (e.g., via XSS) to perform a session escalation attack by exchanging a known session ID for the session ID of an authenticated user. This occurs because the application may establish or transition to an authenticated session without properly invalidating the pre-existing session identifier. Exploitation requires network access and user interaction, with high attack complexity due to the prerequisite of a compromised subdomain. Patches are available in versions 7.0.8 and 6.2.19.

Affected products

  • VMware Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48

Timeline

  • 2026-06-09: disclosed
  • 2026-06-09: advisory
  • 2026-07-30: patched: Updated advisory with patch information

References

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