It's still work in progress, there is not that much information about it available yet (even wolfSSL itself is blank), but according to the very high CVSS score of 9.8 (10 is most severe) it's likely, that this issue has RCE potential.
In wolfSSL prior to version 4.6.0 there exists serious security issue. This wolfSSL library is provided as
libwolfssl24 package in OpenWrt and shipped by default in snapshots since August 27th 2020. It's NOT shipped by default in latest stable OpenWrt release 19.07.
Full advisory can be found on dedicated wiki page.
Package upgrade to fixed
libwolfssl24 version 4.6.0
You need to update the affected
libwolfssl24package you're using with the command below.
opkg update; opkg upgrade libwolfssl24
Then verify, that you're running fixed version.
opkg list-installed libwolfssl24
The above command should output following for stable OpenWrt 19.07 release and snapshot builds:
libwolfssl24 - 4.6.0-stable-1