According to Latvian public news portal
New restrictions come into force on Monday, September 19 that are designed to prevent Russian nationals with Schengen tourist visas from entering or transiting the Baltic States. Poland, too, is enacting similar restrictions. [...]
At an informal meeting of in Prague on 30-31 August [...] a common understanding was achieved among the EU Foreign Ministers that countries bordering on Russia could impose national-level restrictions on entry into the EU, ad that is what most of the countries meeting that criteria have chosen to do. In Finland, debate on the matter is ongoing.
Latvia, Estonia and Lithuania have agreed on their own regional solution so that, pending collective EU action, traveller flows from Russia can be effectively and promptly restricted, thereby reducing security risks. The decision has been adopted in a concerted manner, in cooperation between Latvia, Estonia and Lithuania, and it takes effect simultaneously in the three Baltic States on 19 September 2022 and are of indefinite duration.
It's followed by a list of Schengen visas still allowed, which seems to not include tourists, as per the summary.
Back in the summer, a number of law bloggers had expressed the opinion that some kinds of blanket bans like not issuing any visas to Russians would illegal in the EU. One catch I see with that argumentation is that the aforementioned countries don't seem to not issue visas (by this measure), but essentially plan to not admit persons with some kinds of visas. That possibility (which frankly seemed far more likely/practical) is alas not dissected in that blog.
So have there been any legal challenges announced against this measure? If so on what basis (and by whom)?