security/vuxml: Document MySQL vulnerabilities from CPU Jul 2026

The Oracle Critical Patch Update of July 2026 fixes 54 issues in
Oracle MySQL. 31 of them affect the 8.4 series, 43 the 9.7 series,
including the MySQL Router shipped with the server ports.

Three issues require no credentials: one in the X Plugin and two in
MySQL Router, the latter of which allows unauthorized read and write
access. The remaining ones mostly need a privileged account and lead
to a denial of service.

Fixed in 8.4.11 and 9.7.2 respectively.

Sponsored by: Netzkommune GmbH