OpenResty is a patch release addressing a security vulnerability in the NGINX resolver that may allow an attacker who is able to forge UDP packets from the specified DNS server to cause a 1-byte memory overwrite, resulting in a worker process crash or other unspecified impact. (CVE-2021-23017)

NGINX cores from 0.6.18 to 1.20.0 (included) are affected by this issue. If you are using resolver directive with any previous OpenResty release, upgrade to

The (portable) source code distribution, the Win32/Win64 binary distributions, and the pre-built binary Linux packages for Ubuntu, Debian, Fedora, CentOS, RHEL, OpenSUSE, Amazon Linux are provided on this Download page.

This is the second OpenResty release based on the nginx 1.19.3 core.

Version highlights

  • Upgraded openssl to 1.1.1k for Win32/Win64.
  • Applied the patch for security advisory to NGINX cores >= 0.6.18 and <= 1.20.0 (CVE-2021-23017).

Full Change logs

Complete change logs since the last (formal) release,, can be browsed in the page Change Log for 1.19.3.x.


Feedback on this release is more than welcome. Feel free to create new GitHub issues or send emails to one of our mailing lists.