Ghostfolio - Unauthorized Portfolio Holding Tag Modification via Missing Permission Check

Ghostfolio's PUT /api/v1/portfolio/holding/:dataSource/:symbol/tags endpoint fails to verify Access.permissions field when processing the Impersonation-Id header, allowing read-only access grantees to modify portfolio holding tags. Attackers with valid read-only share tokens can assign or remove tags on victim holdings, corrupting portfolio categorization and reports.