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MonitoringCalifornia AG filing · September 11, 2026

Catalyst Physician Group Data Breach Affects California Patients

Catalyst Physician Group reported a data security incident in California where unauthorized actors accessed their internal systems. This breach exposed a wide range of sensitive patient information, creating significant, long-term risks for those affected. Patients who received a notification letter should understand their potential legal options.

This breach is real, not a scam. Catalyst Physician Group officially reported it to the California Attorney General on September 11, 2026.

Reviewed by David S. Harris, Esq., data breach and class action attorney (Florida Bar No. 0112739). Free consultation: 786-306-7278

Received a Catalyst Physician Group notification letter? Find out in minutes if you qualify for compensation.

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State
California
Breach date
December 2, 2025
Reported
September 11, 2026

What may have been exposed

  • Full Name
  • Date of Birth
  • Social Security Number
  • Medical Record Number
  • Health Insurance ID Number
  • Diagnosis and Treatment Information
  • Prescription Information
  • Provider and Treatment Dates
  • Billing and Financial Information

Catalyst Physician Group, a prominent outpatient medical network operating in California, recently reported a data security incident. The breach, which occurred on December 2, 2025, involved unauthorized access to the group's internal digital environment, leading to the exposure of highly confidential patient data. This incident was formally reported to authorities on September 11, 2026, and is currently under monitoring.

The compromised patient records included sensitive categories such as Full Name, Date of Birth, Social Security Number, Medical Record Number, Health Insurance ID Number, Diagnosis and Treatment Information, Prescription Information, Provider and Treatment Dates, and Billing and Financial Information. Such comprehensive exposure of personal and medical details can have severe and lasting consequences for individuals.

Unlike a compromised credit card, which can be canceled and replaced, core medical and identity data cannot be changed. The exposure of clinical and diagnostic information can open affected individuals to medical fraud, where criminals might use stolen identities to obtain healthcare services or bill insurance providers fraudulently. Furthermore, the combination of Social Security Numbers and Dates of Birth creates a high risk for full identity theft, fraudulent loan applications, and financial account takeovers.

Under both federal and California state privacy laws, including HIPAA, the California Confidentiality of Medical Information Act (CMIA), and the California Consumer Privacy Act (CCPA), healthcare providers like Catalyst Physician Group have a clear legal obligation to implement robust security measures to protect patient data. A breach of this magnitude suggests that the organization may have failed to uphold these essential safeguards, leaving patient information vulnerable to malicious actors.

If you received a data breach notification letter from Catalyst Physician Group, it serves as formal acknowledgment that your private information was compromised due to inadequate data security. The mere exposure of such sensitive data can constitute a compensable injury under California law, meaning you may have legal standing even if you haven't yet experienced direct financial loss. Our team is currently investigating potential class action claims on behalf of impacted patients, and we offer free case reviews with representation on a contingency fee basis, so you pay nothing out of pocket unless we successfully recover compensation for you.

Received the Catalyst Physician Group notification letter? The Catalyst Physician Group case file tracks this filing.

What to do if you were affected

Based on the categories of information reported in this filing, these steps can help limit the risk of identity theft and fraud.

  • Freeze your credit

    Place a free credit freeze with Equifax, Experian, and TransUnion. A freeze blocks new accounts from being opened in your name and can be lifted anytime.

  • Watch your financial accounts

    Review bank and card statements for unfamiliar activity and turn on transaction alerts. Report anything you don't recognize to your bank right away.

  • Check for medical identity theft

    Review the Explanation of Benefits statements from your health insurer for services or claims you never received, which can signal misuse of your medical identity.

  • Stay alert to targeted scams

    Be cautious of calls, texts, or emails that reference this breach. Legitimate organizations won't ask you to confirm sensitive details through an unsolicited message.

  • Keep your notification letter

    Save the notice you received. It documents that your information was involved and is often needed to enroll in any credit monitoring offered or to join a related legal claim.

Catalyst Physician Group data breach lawyer, lawsuit and letter questions

Do I need a Catalyst Physician Group data breach lawyer or attorney?
You don't need to pay to find out. Our data breach attorneys review notices like this one for free, and data breach cases are usually handled on contingency — no fee unless money is recovered for you.
Can I sue Catalyst Physician Group over the data breach?
It depends on what was exposed, the law in California and your own state, and whether you've been harmed. Most people take part through a class action rather than suing alone. Keep your notification letter — it's the proof that connects you to the breach.
How many people were affected by the Catalyst Physician Group data breach, and what was exposed?
The filing does not give a count of affected people and lists the following information as involved: Full Name, Date of Birth, Social Security Number, Medical Record Number, Health Insurance ID Number, Diagnosis and Treatment Information, Prescription Information, Provider and Treatment Dates, Billing and Financial Information. Your own letter is the best guide to what was exposed about you, since notices are usually tailored to each person.
Is there a Catalyst Physician Group data breach class action lawsuit?
Law firms often open an investigation after a breach notice like this one, and a class action lawsuit may follow. This page doesn't confirm that a lawsuit has been filed against Catalyst Physician Group. You usually don't have to join a class action to be included — if a settlement is reached, class members are notified and can file a claim.
Is the Catalyst Physician Group data breach letter legit or a scam?
A notice from Catalyst Physician Group in the mail matches the breach Catalyst Physician Group reported to the California Attorney General on September 11, 2026. Check that the company name and dates in your letter match that filing. A real notice of data security incident won't ask for your password, Social Security number or a payment — if it does, contact Catalyst Physician Group through a phone number or website you find yourself.
Did Catalyst Physician Group offer free credit monitoring?
Any free monitoring Catalyst Physician Group is offering will be described in the notice you received, along with an activation code and a sign-up deadline. Because Social Security numbers are listed in this filing, identity monitoring and a credit freeze matter more than usual. Enrolling does not give up your right to bring a claim.
How much could a Catalyst Physician Group data breach settlement or claim be worth?
There is no set amount, and no Catalyst Physician Group settlement is confirmed here. In past data breach settlements, payments depended on what data was exposed and on documented losses — fraud, out-of-pocket costs and time spent dealing with the breach. The filing lists Full Name, Date of Birth, Social Security Number as involved. Keep receipts and records; they're what damages claims are built on.
Where can I see the official Catalyst Physician Group breach notice?
Catalyst Physician Group's report is published by the California Attorney General: https://oag.ca.gov/privacy/databreach/reporting Compare it with the letter you received to confirm the dates and details match.
What should I do after getting the Catalyst Physician Group data breach notice?
Keep the letter and the envelope, and note the date it arrived. Freeze your credit with Equifax, Experian and TransUnion, change any passwords the notice mentions, and sign up for any free credit monitoring the letter offers. Then check whether you may have a claim.

Source: California Attorney General filing

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