# CVE-2026-41838: VMware Spring Framework predictable WebSocket session IDs

Source: https://junglewise.ai/threats/cve-2026-41838-vmware-spring-framework-predictable-websocket-session-ids  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-09. Updated: 2026-07-29  
License: CC BY 4.0 with a link back

CVE-2026-41838 · Severity: medium · CVSS 4.8 · Published 2026-06-09

Spring Framework is a widely used software development framework for Java applications. A vulnerability in its WebSocket module means that session identifiers are generated in a predictable way rather than being truly random. If an application also has weak security rules, an attacker could potentially guess a user's session ID to gain unauthorized access to their data or communications.

Technologies: [VMware Spring Framework](https://junglewise.ai/threats/technologies/spring-framework). Vendors: [Maven](https://junglewise.ai/threats/vendors/maven), [VMware](https://junglewise.ai/threats/vendors/vmware).

## Quick answers

**Is CVE-2026-41838 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-41838 being exploited in the wild.

**How severe is CVE-2026-41838?** Medium severity, with a CVSS score of 4.8, published 9 June 2026.

**Which products and versions are affected?** org.springframework:spring-websocket (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-2026-41838?** Yes. org.springframework:spring-websocket (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-2026-41838 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-41838?** Check whether you run org.springframework:spring-websocket (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-websocket (Maven): upgrade to 7.0.8 or later

  ```sh
  # set org.springframework:spring-websocket to 7.0.8 in your pom.xml or build.gradle
  ```


## Technical details

A vulnerability exists in the spring-websocket module of the Spring Framework where WebSocket session IDs are generated using a non-cryptographically secure method, leading to predictable values (CWE-330). An attacker with network access and low privileges could potentially predict session IDs, which, when combined with insufficient authorization checks, could lead to unauthorized access to session data. The vulnerability requires high attack complexity and user interaction according to the vendor's CVSS assessment. The issue has been addressed by switching to JdkIdGenerator for session ID generation. Patches are available in versions 7.0.8 and 6.2.19, with other branches requiring updates to their respective latest releases.

## 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-2026-41838
- GHSA-q723-847q-5g8g

## Timeline

- 2026-06-09: disclosed
- 2026-06-09: advisory
- 2026-07-29: patched

## References

- [https://spring.io/security/cve-2026-41838](https://spring.io/security/cve-2026-41838)
- [https://github.com/spring-projects/spring-framework/issues/36740](https://github.com/spring-projects/spring-framework/issues/36740)
- [https://github.com/spring-projects/spring-framework/commit/a42a6e0c6ac64eb18954729ca5e3fe64b05a39b5](https://github.com/spring-projects/spring-framework/commit/a42a6e0c6ac64eb18954729ca5e3fe64b05a39b5)
- [https://github.com/spring-projects/spring-framework/commit/bff98999056fc29b573ff47ad2433462eb52833c](https://github.com/spring-projects/spring-framework/commit/bff98999056fc29b573ff47ad2433462eb52833c)
- [https://github.com/spring-projects/spring-framework/releases/tag/v6.2.19](https://github.com/spring-projects/spring-framework/releases/tag/v6.2.19)

## Related threats

- [Spring Framework stream corruption in Server-Sent Events](https://junglewise.ai/threats/cve-2026-59313-spring-framework-stream-corruption-in-server-sent-events)
- [Spring Framework information disclosure in WebSocket exception handling](https://junglewise.ai/threats/cve-2026-47893-spring-framework-information-disclosure-in-websocket-exception)
- [Spring Framework XML maxInMemorySize enforcement bypass](https://junglewise.ai/threats/cve-2026-47891-spring-framework-xml-maxinmemorysize-enforcement-bypass)
- [Spring Framework UrlHandlerFilter open redirect vulnerability](https://junglewise.ai/threats/cve-2026-47883-spring-framework-urlhandlerfilter-open-redirect-vulnerability)
- [VMware Spring Framework denial of service in static resource resolution](https://junglewise.ai/threats/cve-2026-41842-vmware-spring-framework-dos-in-static-resource-resolution)