Critical vulnerability unknown!?

[richb-hanover-priv]

As is so frequently the case, @hnyman has published a definitive description of the situation, and what you should do about it (TL;DR - nothing, or not much. Read his note)

Security Advisory 2024-12-06-1 - OpenWrt Attended SysUpgrade server (CVE-2024-54143)

In short, you can't. The security problem was about the ASU build process, not about an identified insertion of some code to the image itself. So, there is nothing exact to check in your image. But like efahl said, the real changes of actual compromise are really minimal. If I understand correctly, it would have required the hacker to have prepared a malicious image that is changed to contain malicious code, but still works for your router model and still matches the original hash calculated …