DHS bans DeepSeek, and tools built on it, from agencies

If you sell software to a federal civilian agency and any part of it runs on DeepSeek, it is now on the way out.

The Department of Homeland Security's notice of order, published in the Federal Register on Tuesday, October 20, excludes products and services from Hangzhou DeepSeek Artificial Intelligence and its affiliates from civilian agency purchasing. It also orders agencies to remove DeepSeek products and "third-party products and services developed using DeepSeek implementations" from their IT systems.

That last clause is the one that reaches you.

The order covers what is built on DeepSeek, too

The signed order is Exclusion and Removal Order #2026-01, from Homeland Security Secretary Markwayne Mullin, issued under the Federal Acquisition Supply Chain Security Act of 2018. Its original release date is July 24, 2026. The public notice came Tuesday.

It applies to federal civilian executive branch agencies. National security systems and secure compartmented systems are outside it, and so are the Department of War and the intelligence community, which have their own authority under the same law.

Agencies have two jobs, according to the order:

• Stop buying DeepSeek and its affiliates' products, effective immediately, including through approved product lists and e-commerce markets.
• Remove DeepSeek products, and third-party products built using DeepSeek, from their systems, or ask for an exception.

An agency that wants an exception has to ask in writing within 60 days of the order's issuance, with a "compelling justification." CISA reviews the requests. DHS will review the order within one year and every year after.

The order's stated reasons: DeepSeek's servers are in China, Chinese law gives the government broad access to company infrastructure, and prompts sent to DeepSeek's apps "may result in the transfer of sensitive data to the PRC." It also says the models "may contain malware or other security vulnerabilities," and cites outside research that found flaws in DeepSeek's iOS app.

CyberScoop reports that agencies had already been blocking DeepSeek at their own discretion, and that DeepSeek is the only Chinese AI model maker named in the order. CyberScoop says it asked CISA and DHS for further details.

Open weights do not get you out of it

Here's the thing. The order's scope does not separate DeepSeek's hosted chat app from its open-weight models running on American servers. It names third-party products "developed using DeepSeek implementations," with no carve-out for where the model runs.

That matters because DeepSeek is a default cheap option for a lot of builders. TopFive covered its V4.1 Flash update and new search API on Sunday, and open-weight models carry seven in ten tokens on Vercel. Plenty of products route some traffic to a DeepSeek model without the customer ever knowing.

Until now, that was a cost decision. For federal civilian buyers, it is now a compliance question.

What to do if government is a customer

Find every place a DeepSeek model touches your product. That includes fallbacks in an AI gateway, fine-tunes built on DeepSeek weights, and vendors you call who may use it underneath.

Write it down. A contracting officer asking "does this use DeepSeek" needs a yes or no, and the 60-day exception window belongs to agencies, not to you.

If the answer is yes, swap the model before the question arrives. A model swap is a config change for most stacks. A lost contract is not.

What to watch

Whether the Department of War and the intelligence community issue matching orders under their own authority, since this one stops at civilian agencies.

Whether the next order names another lab. CyberScoop's report points to concerns about Moonshot AI's Kimi and Alibaba's Qwen.

Check your fallbacks before your customer does.