I am wondering if I can use regular scale strings for the Squier Classic Vibe Jaguar bass, which is medium scale
It's always better to find strings of the right length if possible in order to avoid any potential issues. What specific type of strings are you looking for? Or, your preferred brand?
GHS Boomers do come in "medium scale" with 35.5" winding length (ball end to silk). GHS Bass Boomers Nickel Wound Bass String Set Medium Scale - 4-String 45-105 Medium 3040 DR's "short scale" is actually 33.75" in winding length (ball end to taper), which is actually plenty long enough for your bass. The Hi Beams are available in "short scale". DR Hi-Beam Stainless Steel Electric Bass Strings Short Scale Set 4-String 45-105 Medium SMR-45 I live in Winnipeg, and I usually get my strings from Jason at Fret Nation.
Let us all repeat the mantra: 1) measure from the string anchor to the tuner side of the nut; 2) measure from the string anchor to the middle of the E string tuner post; 3) purchase a set of strings that the winding length, or speaking length, is between these two measurements. Contact the manufacturer if the winding length is not published.
I have the single-humbucker 32" scale Jaguar and put D'addario XL long scale (normally fit 34" scale) on it with no problems at all.