Short answer
Mittwald, a German hosting provider, says an attacker gained unauthorized access to its MCP server on 27 October 2026 and read user session tokens, then used them in the mStudio control panel. The company detected the activity on 4 November and says no passwords were stolen. Customers who never used the MCP server are not affected so far.
If you think your details were included, start with our checklist on what to do after a data breach.
Key facts
| Organization | Mittwald CM Service |
|---|---|
| Incident type | Account takeover |
| Status | Confirmed by the organization |
| Sector | Web hosting |
| Country | Germany |
| Detected | 2026-11-04 |
| Disclosed | 2026-11-05 |
| People or records affected | Customers who used the Mittwald MCP server (number not given) |
What data was exposed
- Session tokens of customers who used the MCP server (confirmed)
- Access to those customers' mStudio projects with their permissions (confirmed)
- Project data, credentials or files stored in those projects (not confirmed either way)
What happened
Mittwald is a hosting provider in Espelkamp, Germany, whose customers are mostly agencies and freelancers who run client sites through its mStudio control panel. On 5 November 2026 the company published a timeline and FAQ about an attack on its MCP server, a service that lets tools and AI assistants act on a customer’s projects.
According to Mittwald, someone gained unauthorized access to the MCP server on 27 October and read the session tokens of its users. Those tokens gave access to the users’ mStudio projects with their normal permissions. Mittwald says it detected the activity through its own analysis on 4 November.
What the company did
Mittwald shut down the MCP server and revoked all tokens. On 5 November it disabled the mStudio login, ended and blocked SSH connections, and switched off its Extensions as a precaution. Later that day it confirmed unauthorized access to mStudio through the MCP server. Borns IT- und Windows-Blog reported the same sequence and noted that hosted sites and email stayed online.
By 6 November Mittwald said its security work was nearing completion and that the mStudio login would return in steps. Projects with signs of attacker activity are taken offline until they have been scanned.
What is confirmed and what is not
Confirmed by the company: tokens were read and used. Not confirmed: whether any project files, databases or stored credentials were copied. Mittwald says it has no evidence that data was published and will contact customers directly if it finds signs of access. It has not said how many customers used the MCP server or who is behind the attack.
Some customers on the blog say the SSH block stops them applying security updates, and a few say they plan to move providers. Those comments are unverified.
Why this matters for scams
Hosting accounts are valuable because one login can reach many client websites. A stolen token can let an attacker add a hidden file, create an SSH user or read stored email and database logins. Follow-on scams include phishing pages on a trusted domain and fake “Mittwald security” emails. Our guides on phishing messages and fake invoice and business email scams cover the common patterns, and what to do after a data breach lists the basics.
Steps for site owners
Work through Mittwald’s list in order: password, two-factor authentication, keys and tokens, then third-party credentials stored in your projects. If you restore a backup, Mittwald says it will discuss with you which changes made since 27 October to keep.
More incidents are in our breach tracker.
Scams to watch for after this breach
Criminals use breach news as cover. Expect messages that mention the incident, quote real details, or offer help.
- Phishing emails posing as Mittwald, asking you to log in to mStudio or reset credentials through a link.
- Hacked customer websites used to host phishing pages or malware, if an attacker placed files in a project.
- Fake security alerts to website owners that ask for SSH keys, API tokens or database passwords.
- Abuse of mailboxes or database logins stored in a project to send spam or scam messages in the site owner's name.
What to do if you are affected
- 01If you used the Mittwald MCP server, change your mStudio password and turn on two-factor authentication.
- 02Review API keys, project tokens and SSH keys in your projects and delete any you do not recognize, including SSH users you did not create.
- 03Renew third-party credentials stored in your projects, such as database, email and external API passwords.
- 04Tell the users of your websites if there is any sign of access, and check your sites for files you did not upload.
- 05Only use the status page or the FAQ on mittwald.de, and treat emails with links about the incident with care.
Frequently asked questions
Was I affected by the Mittwald incident?
Mittwald says that if you never used its MCP server, your mStudio access, projects and data are not affected based on current findings. Customers who did use it were told to expect a personal email.
Were passwords stolen?
According to Mittwald, no passwords were stolen, only session tokens. It still advises MCP users to change their mStudio password.
Are websites hosted at Mittwald offline?
Mittwald and Borns IT- und Windows-Blog report that hosted websites stayed reachable. A small share of projects was deactivated for security scans, and those customers were emailed.
Is there evidence that customer data was published?
Mittwald says it has found no evidence that data was published online. It says it will contact customers directly if it sees signs that project data was accessed.
Why was the attack found a week after it began?
Mittwald says the attacker's activity looked like normal use until 4 November. Commenters on the blog question the gap, but those are opinions, not findings.
Sources
- Mittwald MCP-Server Vorfall: FAQ und Zeitleiste, Mittwald, 2026-11-06
- Hoster Mittwald Opfer eines Cyberangriffs (5.11.2026), Borns IT- und Windows-Blog, 2026-11-05
This post summarises public reporting as of 2026-11-06. Details of live incidents change; we update posts when the organization or regulators publish new facts. Spot an error? See our editorial and corrections policy.