Updated

Some thoughts on this ported over from the bird app. Not a crisis unless you are a submarine swapper. Even so, upgrade anyway 1/9 Electrum 4.8.1 contains “important security fixes”, but the maintainers have not yet disclosed the details. I reviewed the public 4.8.0→4.8.1 code changes. Here is what the evidence does—and does not—show. 🧵 2/9 First: Electrum-generated seeds are not shown to share the COLDCARD entropy flaw. Electrum’s seed-generation code did not change between 4.8.0 and 4.8.1; it uses Python’s cryptographic secrets.randbelow(), backed by the operating system’s CSPRNG. 3/9 The COLDCARD issue arose from a different mechanism: affected device-generated seeds could fall back to weak PRNG/reseed paths. Importing such a seed into Electrum cannot repair it. But an Electrum-generated seed is not weakened merely by later importing it into COLDCARD. 4/9 The critical question is where the seed was originally generated. Genuine Electrum + a normal, uncompromised OS: no analogous entropy defect found. Affected COLDCARD firmware: migrate the seed. Unknown origin: investigate, and take the conservative path if needed. 5/9 The BTCPay incident was separate: it exposed LND macaroon credentials in affected BTCPay deployments. Electrum’s built-in Lightning wallet is not LND and does not use those macaroons. This was not an Electrum seed-generation flaw. 6/9 Visible 4.8.1 hardening includes malicious-server resource limits, stricter network-response validation, CPU-DoS bounds, oversized base43 input limits, log redaction, Android screenshot protection, and Lightning/swap safety checks. 7/9 Our best inference: the undisclosed fix is the submarine-swap fund-safety cluster—funding without expected HTLCs, cancel/broadcast races, unsafe provider terms and refund-reorg timing. This is a code-based inference, not confirmation from Electrum’s maintainers. 8/9 Practical takeaway: upgrade to a verified Electrum 4.8.1 release before connected use. Do not rotate a genuinely Electrum-generated seed solely because of the COLDCARD incident. If the seed came from affected COLDCARD firmware, follow its migration guidance urgently. 9/9 It boils down to PR #10827, framed as a unit test but actually is the submarine swap flaw. If you are a lightning person (like us) take note. No issue with @ElectrumWallet doing it this way; there aren't many choices when it's all open spurce

Also thank you to Thomas for what can not have been an easy week

Looking forward to the disclosure of the details