OPNsense is a FreeBSD based firewall and routing platform. Prior to 26.1.11, OPNsense\Core\ACL::hasPrivilege() appends a directly assigned comma-separated <priv> value as one string and then uses an exact comparison when checking user-config-readonly. A user directly assigned both a component write privilege and user-config-readonly can therefore be treated as lacking the read-only restriction, and MVC APIs protected by throwReadOnly() can persist configuration changes for that component. Group privileges are not affected by the same parser flaw because the group path already splits comma-separated values. This issue is fixed in version 26.1.11.