Envoy version 1.26.3 fixes a memory leak which was found in the nghttp2 library, which is also used by Apache HTTP Server.
Airlock Gateway and Airlock Microgateway are not affected.
The memory leak can only by triggered by a crafted response from an untrusted upstream service. As upstream servers behind Airlock Gateway and Microgateway are trusted, the vulnerability cannot be exploited.
No action required.