Impact
This is an RCE vulnerability that affects Craft 4 and 5 installs where your security key has already been compromised.
https://craftcms.com/knowledge-base/securing-craft#keep-your-secrets-secret
Anyone running an unpatched version of Craft with a compromised security key is affected.
Patches
This has been patched in Craft 5.5.8 and 4.13.8.
Workarounds
If you can't update to a patched version, then rotating your security key and ensuring its privacy will help to migitgate the issue.
References
e59e22b
Impact
This is an RCE vulnerability that affects Craft 4 and 5 installs where your security key has already been compromised.
https://craftcms.com/knowledge-base/securing-craft#keep-your-secrets-secret
Anyone running an unpatched version of Craft with a compromised security key is affected.
Patches
This has been patched in Craft 5.5.8 and 4.13.8.
Workarounds
If you can't update to a patched version, then rotating your security key and ensuring its privacy will help to migitgate the issue.
References
e59e22b