CVE-2021-23017

Name of the Vulnerable Software and Affected Versions nginx versions 1.20.0

Description A security issue in the nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause a 1-byte memory overwrite, resulting in a worker process crash or potential other impact. The issue is related to an off-by-one heap write vulnerability in the ngx resolver copy() function.

Recommendations For nginx version 1.20.0, update to a newer version that contains a fix for this issue. As a temporary workaround, consider restricting access to the DNS resolver to minimize the risk of exploitation.