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

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

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.

Technologies: org.springframework:spring-webflux (Maven), VMware Spring Framework. Vendors: Maven, VMware.

Quick answers

Is CVE-2026-41839 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-41839 being exploited in the wild.
How severe is CVE-2026-41839?
Medium severity, with a CVSS score of 4.2, published 9 June 2026.
Which products and versions are affected?
org.springframework:spring-webflux (Maven) ECOSYSTEM:introduced=7.0.0,fixed=7.0.8; 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.
Is there a fix for CVE-2026-41839?
Yes. org.springframework:spring-webflux (Maven): upgrade to 7.0.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-41839 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-41839?
Check whether you run org.springframework:spring-webflux (Maven) or VMware Spring Framework at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • org.springframework:spring-webflux (Maven): upgrade to 7.0.8 or later
    # set org.springframework:spring-webflux to 7.0.8 in your pom.xml or build.gradle

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

Identifiers

  • CVE-2026-41839
  • GHSA-4hfh-6x8g-gwpp

Timeline

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

References

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