stunnel 5.55 released

Michał Trojnara Michal.Trojnara at
Mon Jun 10 16:09:32 UTC 2019

Dear Users,

I have released version 5.55 of stunnel.
This release addresses a number of important Windows issues, including
security vulnerabilities.

Version 5.55, 2019.06.10, urgency: HIGH
* Security bugfixes
  - Fixed a Windows local privilege escalation vulnerability
    caused insecure OpenSSL cross-compilation defaults.
    Successful exploitation requires stunnel to be deployed
    as a Windows service, and user-writable C:\ folder. This
    vulnerability was discovered and reported by Rich Mirch.
  - OpenSSL DLLs updated to version 1.1.1c.
* Bugfixes
  - Implemented a workaround for Windows hangs caused by its
    inability to the monitor the same socket descriptor from
    multiple threads.
  - Windows configuration (including cryptographic keys)
    is now completely removed at uninstall.
  - A number of testing framework fixes and improvements.

Home page:

SHA-256 hashes:

Best regards,

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