Honestly, this exact thing happened to my cousin and the reason turned out to be something she never would have guessed. Let me walk you through what to actually look for.
First, the most likely culprits:
**Credit utilization spike.** This is the big one most people miss. Even if you pay your card in full, CIBIL captures your balance on the *statement date*, not the payment date. So if you spent ₹40k on a ₹50k limit card in a month — even temporarily — your utilization shot up to 80% and that tanks your score hard. Check what your outstanding balance was when the statement was generated, not when you paid.
**Hard inquiry you forgot about.** You mentioned checking your score twice. Checking your own score on CIBIL app is a soft inquiry, doesn't affect score. But did you apply for anything else? A new credit card, even just browsing on BankBazaar or Paisabazaar sometimes triggers a hard pull if you filled in details and clicked 'check eligibility.' That alone can drop 15-20 points, and multiple ones compound.
**Closed account affecting credit age.** If any old credit card got closed — either by you or by the bank due to inactivity — your average credit age drops. This silently kills scores.
**Address/identity mismatch updating.** Sometimes a lender updates your KYC details and it creates a flag in the bureau. Rare but happens.
Now for the fraud concern — yes, take it seriously. Go to the full CIBIL report (not just the score), scroll to the 'Accounts' and 'Enquiries' section. If you see any loan or card you never applied for, immediately raise a dispute on CIBIL's portal and file a complaint with RBI's Banking Ombudsman.
For the home loan timeline — 681 is workable but not ideal. Most PSU banks like SBI want 700+ for best rates, private banks like HDFC prefer 720+. You have 3-4 months, which is actually enough time to recover if the drop was utilization-related. Keep utilization under 30%, don't apply for anything new, and let the score self-correct.
My honest recommendation: download the full detailed report from CIBIL (₹550 for the detailed one, worth every rupee), check the enquiries tab first, then utilization history. That will tell you exactly what happened.