Some forums claim CS5 is "abandonware" (software no longer sold or supported by its publisher), making it legal to download for free. Abandonware is not a legal defense. Adobe still holds the copyright to CS5. Sharing the installer is still copyright infringement.
When you search for , you will find two types of results: legitimate (but tricky) and illegitimate (but dangerous).
Adobe now offers a Photography Plan (Photoshop + Lightroom) for roughly $9.99/month. You get the latest features (AI neural filters, sky replacement, Object Selection Tool) and it runs natively on Windows 11 and macOS. If you use it professionally, this is the only correct answer.