high severity December 13, 2023 · 4 min read Unverified claim — what this is

cms.law Listed by lockbit3 Ransomware Group

If you are a customer of cms.law, here’s what is being claimed, and what it would mean for you.

As the largest law firm in Europe, we are able to cover your needs across the entire continent. Whether you are a company with a complex legal issue that crosses European jurisdictions or are seeking local law guidance in a new business market, we ha...
— from LockBit’s own leak-site posting. This is the group’s claim, quoted verbatim; it is not GalaxyWarden’s reporting and has not been independently verified.

cms.law Listed by lockbit3 Ransomware Group

On December 13, 2023, international law firm CMS appeared on the LockBit 3.0 ransomware leak site, claiming that the group had exfiltrated internal files during a ransomware attack on the organization.

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Reported Details from the Listing

The LockBit 3.0 leak page states that internal files were taken from CMS during a ransomware incident. The disclosure does not specify the volume of data, the exact systems compromised, or name any particular categories of documents. It simply lists the firm and provides a countdown timer typical of the group’s extortion process. The primary source, hosted on the LockBit infrastructure and mirrored on ransomware.live, remains the sole official public record of the claim at the time of first disclosure.

CMS, one of Europe’s largest law firms with offices across the continent, handles complex cross-border matters for corporate clients. Any internal files taken could therefore contain sensitive correspondence, case materials, or business records, though the leak-site listing does not detail what was taken.

Why This Matters for You and Your Family

When a major law firm suffers a breach, the ripple effects reach far beyond its corporate clients. If you or your family have ever used legal services—whether for estate planning, property transactions, immigration, employment disputes, or business formation—your personal information may sit inside the very files now in attackers’ hands. Even if your name is not on the front page of any leaked document, metadata, email threads, or supporting schedules often contain dates of birth, addresses, phone numbers, bank details, and family relationships.

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value redacted in this sampleage, relatives, address historySpokeo

value redacted in this samplephone, household, property recordsBeenVerified

value redacted in this sample580 companies checked

Found in breach recordsverifiedreported — unverified

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verifiedvalue redacted in this samplepassword + phone · 2024telecom breach

unverifiedvalue redacted in this sampleclaimed in ransomware listing · 2026leak-site claim

Leaked data cannot be deleted from the internet — anyone claiming otherwise is lying. Broker listings can be removed. We do the second, and show you exactly what to fix from the first.

Report details & sourcing

Attributed to LockBit · 3412 incidents tracked →

Severity High the filing does not enumerate what was exposed

Disclosed December 13, 2023

Last reviewed August 8, 2026

Affected Unconfirmed

By GalaxyWarden Threat Research · Editorial & sourcing standards

Unverified claim — what this report is

This page documents a public listing on a ransomware/extortion group’s leak site, tracked via public threat-intelligence sources. A listing is the attacker’s claim. GalaxyWarden aggregates and reports such claims; we have not independently verified that a breach occurred, what data (if any) was taken, or the accuracy of anything the group asserts, and the named organisation has not necessarily confirmed the incident. Sections above describe what the listing shows and the group’s documented history — not verified findings about the named organisation. If you represent this organisation and believe anything here is inaccurate, tell us and we’ll review it promptly.

Editorial & sourcing policy

GalaxyWarden is a breach-monitoring service and news aggregator. We do not exfiltrate, host, purchase, or redistribute stolen data. Breach information is compiled from publicly accessible sources and threat-intelligence platforms, and is reported as claims attributed to their source. We promptly correct or remove material shown to be inaccurate — see our content & takedown policy or write to support@galaxywarden.com.

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LockBit — 3412 incidents tracked

Every breach we've attributed to LockBit, in one running log. See who else they've hit →

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