PTAB challenges

Proceedings Overview

There is one pending Inter Partes Review (IPR) filed against U.S. Patent No. 12,301,628, which means the patent's validity is actively being challenged at the Patent Trial and Appeal Board (PTAB), offering a significant defensive opportunity for a company facing an infringement assertion.

IPR2026-00326 — Microsoft Corporation v. Qomplx Inc.

• Type: Inter Partes Review
• Filed: 2026-04-03
• Status: Pending. This proceeding is in its initial phase. The Patent Trial and Appeal Board has not yet decided whether to institute a trial.
• Judge panel: A judge panel has not yet been made public for this proceeding.
• Petition grounds: The IPR petition challenges claims 1-8 of the '628 patent as being obvious under 35 U.S.C. § 103 over a combination of prior art references. The primary combination asserts that the claimed invention is an obvious combination of the applicant's own prior art patents:
  • Crabtree '464 (US 2017/0124464), which teaches the creation of a "cyber-physical system graph."
  • Crabtree '910 (US 10,248,910), which teaches cybersecurity behavioral analytics to identify anomalies.
  • Crabtree '147 (US 10,204,147), which teaches using the graph to calculate a "blast radius" by correlating affected resources.
• Institution decision: A decision on whether to institute a trial is not yet due. The statutory deadline for the PTAB to issue an institution decision is approximately October 3, 2026.
• Final Written Decision: Not yet issued. If a trial is instituted, a Final Written Decision would be due within one year of the institution date, approximately October 2027.
• Settlement / termination: There is no public record of settlement or termination.
• Appeal: Not applicable.
• Defensive value: This proceeding is highly valuable for a defendant. It indicates that Microsoft, a major technology company and co-defendant in parallel district court litigation, has identified what it believes are strong invalidity arguments. The petition and its accompanying expert declaration can serve as a detailed roadmap for another defendant's own invalidity contentions, potentially saving significant research and expert costs.

Strategic summary

Currently, all claims of the '628 patent remain valid and enforceable, as no PTAB proceeding has reached a final decision. However, claims 1-8 are under a significant challenge in IPR2026-00326. The patent has not been tested or narrowed in any prior PTAB proceeding.

Regarding estoppel, no party is currently estopped from challenging the '628 patent at the PTAB. If the pending IPR against Microsoft results in a Final Written Decision, Microsoft and any "real party in interest or privy" would be barred under 35 U.S.C. § 315(e)(2) from later asserting in district court or the ITC that the claims are invalid on any ground that they raised or reasonably could have raised in the IPR. Other potential defendants are not subject to this estoppel and can use the same art combinations, or different ones, in their own IPRs or in court.

The pattern here is clear: Microsoft's IPR filing is a direct defensive response to the district court litigation brought by Qomplx LLC. This is a standard tactic used by defendants to create a parallel, often faster and less expensive, proceeding at the PTAB to invalidate the asserted patent.

Recommended next steps

For a defendant currently facing an assertion of US Patent 12,301,628:

• Closely Monitor IPR2026-00326: The most critical upcoming milestone is the PTAB's institution decision, expected on or before October 3, 2026. A decision to institute would indicate the PTAB believes there is a "reasonable likelihood" that Microsoft will prevail in proving at least one challenged claim unpatentable.
• Obtain and Analyze the IPR Petition: The petition filed by Microsoft is a public document available on the PTAB's End-to-End (E2E) system. It contains a detailed breakdown of the prior art and expert testimony arguing for the invalidity of claims 1-8. This document is an invaluable resource for developing your own invalidity strategy. You can access the case file here: USPTO PTAB E2E for IPR2026-00326.
• Evaluate a "Tag-Along" IPR: Consider filing your own IPR petition against the '628 patent. You can leverage the arguments and art presented by Microsoft, potentially adding new references or improving upon their arguments. This would give you a seat at the table and prevent your case from being stayed pending the outcome of Microsoft's IPR without your direct involvement.
• Use the IPR in District Court Proceedings: The existence of the pending IPR can be a powerful tool in district court. You can use it to argue for a stay of the litigation pending the PTAB's review, which, if granted, could significantly delay and reduce litigation costs.