In Spring Framework, versions 5.2.x prior to 5.2.15 and versions 5.3.x prior to 5.3.7, a WebFlux application is vulnerable to a privilege escalation: by (re)creating the temporary storage directory, a locally authenticated malicious user can read or modify files that have been uploaded to the WebFlux application, or overwrite arbitrary files with multipart request data.

Spring MVC applications are not affected by this vulnerability, nor are applications that do not handle multipart file requests.

• Spring Framework
  • 5.2.0 to 5.2.14
  • 5.3.0 to 5.3.6

Users of affected versions should apply the following mitigation. 5.3.x users should upgrade to 5.3.7. 5.2.x users should upgrade to 5.2.15. No other steps are necessary. Releases that have fixed this issue include:

• Spring Framework
  • 5.3.7
  • 5.2.15

This issue was identified and responsibly reported by Trung Pham from Viettel Cyber Security.