Merge pull request #11385

What changed, and why it matters

This commit adds cleanup of three additional memory buffers in Monero's seed-phrase key-stretching code. Before the change, leftover copies of intermediate secrets could remain in stack memory after the function finished. An attacker who could read process memory (for example, through another vulnerability or a memory dump) might recover parts of a wallet's seed-phrase secret. The patch wipes those buffers before returning, reducing that exposure.

Security signals we found

Evidence from the diff

Changed components

### src/mnemonics/polyseed/pbkdf2.c
@@ -82,4 +82,7 @@ crypto_pbkdf2_sha256(const uint8_t* passwd, size_t passwdlen,
     }
     sodium_memzero((void*)&Phctx, sizeof Phctx);
     sodium_memzero((void*)&PShctx, sizeof PShctx);
+    sodium_memzero((void*)&hctx, sizeof hctx);
+    sodium_memzero((void*)U, sizeof U);
+    sodium_memzero((void*)T, sizeof T);
 }