This is a bug affecting Clair 4.6.1(and also previous releases I guess).

When the user tries to export the updaters bundle, clairctl will report this error:

2023-07-19T12:34:07Z ERR error="updating errors:\ndebian/updater/bookworm: vulnerability database parse failed: debian: unable to decode OVAL document: XML syntax error on line 1: invalid character entity &SY� (no semicolon)\n" 

The issue is related to the way Debian publishes its OVAL files on https://www.debian.org/security/oval/.
They recently transitioned to bzip2 compressed OVAL files and this change is incompatible with Clair right now.
The issue has already been reported on GitHub, link

The issue is 100% reproducible, here you can find the steps for reproducing it:

1. Spin up a Clair instance
2. Run the following command

   1. clairctl --config <path-to-clair-config-file> export-updaters <updaters-bundle-file-name> 

It looks like this issue has already been fixed in this upstream [PR|https://github.com/quay/claircore/pull/888] I'm creating this Jira just for tracking purposes.