---
title: Crédit Mutuel Arkéa confirms a cyberattack let attackers make fraudulent transactions; on-chain tracing puts the theft at $133M+, the bank says 'several tens of millions of euros' and no client losses | ctxsec
url: https://ctxsec.com/items/credit-mutuel-arkea-confirms-cyberattack-fraudulent-operations-nov-4
description: "The Brittany-based French banking group (the Cr\u00e9dit Mutuel de Bretagne and Sud-Ouest federations) said on Nov 4 it was hit by an attack that allowed 'fraudulent operations', that the incident is now under control, and that clients will bear no financial loss. It temporarily suspended some transactions and says they will resume after final security checks; its app was unavailable on Wednesday morning, per franceinfo. The bank told Le Parisien part of the funds were frozen and the amount is still being assessed at 'several tens of millions of euros'. On-chain investigator ZachXBT, who first flagged the withdrawals, traced more than $133M moved through Kraken, Crypto.com and OKX accounts and swapped to ETH and Monero. The bank notified its supervisors; it has not said how the attackers got in."
status: "official (Crédit Mutuel Arkéa press statement, Nov 4, via AFP/France 24, franceinfo, Le Parisien). The $133M figure is ZachXBT's and Le Télégramme's; the bank has not confirmed it"
published: 2026-11-04
---

> The Brittany-based French banking group (the Crédit Mutuel de Bretagne and Sud-Ouest federations) said on Nov 4 it was hit by an attack that allowed 'fraudulent operations', that the incident is now under control, and that clients will bear no financial loss. It temporarily suspended some transactions and says they will resume after final security checks; its app was unavailable on Wednesday morning, per franceinfo. The bank told Le Parisien part of the funds were frozen and the amount is still being assessed at 'several tens of millions of euros'. On-chain investigator ZachXBT, who first flagged the withdrawals, traced more than $133M moved through Kraken, Crypto.com and OKX accounts and swapped to ETH and Monero. The bank notified its supervisors; it has not said how the attackers got in.

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official (Crédit Mutuel Arkéa press statement, Nov 4, via AFP/France 24, franceinfo, Le Parisien). The $133M figure is ZachXBT's and Le Télégramme's; the bank has not confirmed it

2026-11-04

### Crédit Mutuel Arkéa confirms a cyberattack let attackers make fraudulent transactions; on-chain tracing puts the theft at $133M+, the bank says 'several tens of millions of euros' and no client losses

- **Timeline:** L'Agefi says the incident happened on Nov 1; ZachXBT reported suspicious withdrawals on Nov 2 before naming the bank.
- **Not disclosed:** the entry point, whether internal systems or the bank's own exchange accounts were compromised, and the final amount.
- **Exchanges:** Kraken restricted the linked accounts and Crypto.com blocked related funds (per Cointelegraph, Nov 3).

**For banks and fintechs:** this is a rare case of fiat moved out of a bank and laundered through exchange accounts in hours. Worth checking: alerting on large outbound transfers to newly added exchange counterparties, and how fast your treasury and payments teams can freeze outbound rails.

Sources: [France 24/AFP: Crédit Mutuel Arkéa victime d'une cyberattaque (Nov 4)](https://www.france24.com/fr/info-en-continu/20261104-cr%C3%A9dit-mutuel-ark%C3%A9a-victime-d-une-cyberattaque-ayant-permis-des-op%C3%A9rations-frauduleuses) · [franceinfo: piratage de plus de 100 millions d'euros (Nov 4)](https://www.franceinfo.fr/economie/fraude/le-credit-mutuel-arkea-bretagne-victime-d-un-piratage-de-plus-de-100-millions-d-euros-sans-repercussion-pour-les-clients_8267399.html) · [Le Parisien: bank says several tens of millions, amount being assessed (Nov 4)](https://www.leparisien.fr/high-tech/le-groupe-bancaire-credit-mutuel-arkea-annonce-avoir-ete-victime-dune-cyberattaque-ayant-permis-des-operations-frauduleuses-04-11-2026-IRL4BUQQOVAQVBP6DFCTKHS4VU.php) · [Cointelegraph: ZachXBT names Crédit Mutuel Arkéa (Nov 4)](https://cointelegraph.com/news/zachxbt-french-bank-credit-mutuel-arkea-133m-crypto-theft)