On September 15, 2026, NIST and CISA released NIST IR 8587, giving organizations concrete steps to prevent theft and forgery of access tokens. The publication cites an attack in which forged tokens derived from one stolen signing key let attackers steal more than 60,000 emails from a single agency.
NIST IR 8587 provides implementation guidance for protecting access tokens and identity assertions from forgery, theft and misuse. It responds to requirements set out in Executive Order 14306 and builds on recent updates to the security control catalog SP 800-53. The primary audience is federal agencies and their cloud providers, but NIST says the guidance applies to any organization that relies on tokens for access management, including companies running AI agent infrastructure.
The need is concrete: the report describes an attack in which foreign actors used forged tokens derived from a single stolen commercial signing key to break into an agency email system and steal more than 60,000 messages. Compared with the December 2025 draft, the rules on protecting cryptographic keys are now less prescriptive and more outcome based. New sections cover high level considerations for handling AI systems and migrating to post quantum cryptography, plus additional options for token revocation and sharing security signals.
The publication explicitly does not offer a full toolkit for AI identity or post quantum migration; NIST points to separate work from its center of excellence, NCCoE, for that. For companies running their own identity infrastructure, the practical takeaway is to compare current key management practices against the new recommendations now, even without a direct regulatory mandate. It remains open how quickly cloud providers will fold the revised guidance into their default configurations.
What this means for decision-makers
- Check your token and key management practices against the NIST IR 8587 recommendations.
- Decide how you rotate and protect cryptographic signing keys against theft.
- Track NCCoE follow up work on AI agent identity and post quantum migration.
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