`monero-wallet-rpc::rescan_spent` accepts daemon-supplied spent-status from an untrusted daemon, enabling ring-intersection attack on transactions

Bug reported by offset was disclosed at November 2, 2026, 6:43 pm   |   Information Disclosure

A vulnerability was discovered in the wallet RPC server's rescan spent handler, which failed to verify daemon trustworthiness before accepting spent-status information. The handler invoked the rescan spent function without checking the is_trusted_daemon flag, unlike all other callers of the same function. This allowed a malicious daemon to return incorrect spent status for outputs, causing the wallet to mark previously spent outputs as unspent. When a user subsequently initiated a transaction, the input selector could reuse the marked output as an available input, resulting in the construction of a new ring signature around the same key image. This created two separate ring signatures over identical key images that could be analyzed through ring intersection attacks to compromise transaction privacy.