---
title: "Crédit Mutuel Arkéa unauthorized-transfer incident"
description: "Crédit Mutuel Arkéa disclosed unauthorized transfers of bank funds through a service-provider platform, with temporary transaction delays."
incident_type: "Cybersecurity incident"
status: "active"
last_modified: "2026-11-07"
canonical_url: "https://www.ally.security/incidents/credit-mutuel-arkea-unauthorized-transfer-incident-2026"
markdown_url: "https://www.ally.security/incidents/credit-mutuel-arkea-unauthorized-transfer-incident-2026.md"
stix_url: "https://www.ally.security/incidents/credit-mutuel-arkea-unauthorized-transfer-incident-2026/stix.json"
---

# Crédit Mutuel Arkéa unauthorized-transfer incident

Crédit Mutuel Arkéa disclosed unauthorized transfers of bank funds through a service-provider platform, with temporary transaction delays.

Last modified Nov 7, 2026 · 1 source

## Summary

- **Environment:** Service-provider platform and bank transfer operations
- **Operational impact:** Transfers delayed; most operations resumed November 4
- **Financial impact:** Final loss and recovered funds not quantified

## What happened

[Crédit Mutuel Arkéa](https://www.cm-arkea.com/) said an attacker entered through an unnamed service-provider platform and initiated transfers from an account belonging to the bank. The bank said customer accounts and assets were unaffected. [1](#source-1)

## Impact

The bank temporarily suspended some transactions, delaying transfers, and said most operations had resumed by the morning of November 4 after security checks. [1](#source-1)

## Timeline

### November 4, 2026 — Bank discloses attack and partial operational recovery

Arkéa described unauthorized transfers of bank funds and said most operations had resumed that morning. [Source account](https://www.cm-arkea.com/arkea/banque/assurances/pa_38386/fr/informations-complementaires-suite-a-l-attaque-dont-le-credit-mutuel-arkea-a-ete-victime). [1](#source-1)

### November 7, 2026 — Briefing updated

This briefing was last reviewed and updated on November 7, 2026.

## Threat Group & Attack Vector

Arkéa identified an unnamed service-provider platform as the entry point. The detailed exploit and attacker identity remain undisclosed. [1](#source-1)

### Actors

- No threat actor group has been identified in the reviewed public evidence.

### TTPs

- No specific MITRE ATT\&CK technique is currently mapped for this case.

## Response

Arkéa said the attack was contained, authorities and regulators were informed, and recovery of transferred funds was underway. It did not confirm a finalized loss or the reported €118 million amount. [1](#source-1)

## Assets

[Download the case-scoped STIX 2.1 bundle](<https://www.ally.security/incidents/credit-mutuel-arkea-unauthorized-transfer-incident-2026/stix.json>)

## Sources

Primary source records used to research this incident.

<a id="source-1"></a>

### Informations complémentaires suite à l’attaque dont le Crédit Mutuel Arkéa a été victime

official · Crédit Mutuel Arkéa · Nov 4, 2026

<https://www.cm-arkea.com/arkea/banque/assurances/pa_38386/fr/informations-complementaires-suite-a-l-attaque-dont-le-credit-mutuel-arkea-a-ete-victime>

<details>
<summary>Evidence ledger</summary>

Review the supporting structured claims.

1. **Resulted In · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: Crédit Mutuel Arkéa said an attacker entered through an unnamed service-provider platform and initiated transfers from an account belonging to the bank. The bank said customer accounts and assets were unaffected.
2. **Resulted In · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: Bank discloses attack and partial operational recovery
3. **Affected Organization · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: Crédit Mutuel Arkéa
4. **Resulted In · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: The bank temporarily suspended some transactions, delaying transfers, and said most operations had resumed by the morning of November 4 after security checks.
5. **Resulted In · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: Arkéa said the attack was contained, authorities and regulators were informed, and recovery of transferred funds was underway. It did not confirm a finalized loss or the reported €118 million amount.
6. **Occurred At · 100% confidence · current**  
   Bank discloses attack and partial operational recovery: 2026-11-04
7. **Disclosed At · 100% confidence · current**  
   Crédit Mutuel Arkéa unauthorized-transfer incident: 2026-11-04

</details>