Claude and Codex agents find critical vulnerability in Miden zkVM

Security firm Trail of Bits published a report on the audit of the Miden zkVM, in which Claude and Codex agents built four tools from scratch over six months, finding 400+ instances of missing type validation in the public API and a critical mod_12289 vulnerability that allowed a malicious prover to forge Falcon signatures and drain accounts.

Compiled by Sergey KostenchukPublished 2026-09-21Updated 2026-09-22

2026-09-21 Safety Anthropic

🛡 Claude and Codex agents find critical vulnerability in Miden zkVM

Over six months, Claude and Codex agents built an LSP server, a decompiler, a static analyzer, and a formal VM model in Lean for the Miden zkVM audit. The tools found 400+ instances of missing type validation in the public API and the mod_12289 bug: a malicious prover could forge Falcon signatures and drain accounts.

🌍 The economics of auditing are changing: custom tooling for a language without an IDE and linters can be built in months, making decompilation and Lean verification accessible to niche zk projects. Miden has already implemented the analyzer to check core library updates.

👤 A proven template: Claude plans, Codex reviews, and findings become regression tests—this is how fund-draining bugs are caught, not just style issues. All four tools are open on GitHub.

Source 1: https://blog.trailofbits.com/2026/09/18/auditing-in-the-age-of-good-enough-ai/

Source 2: https://github.com/trailofbits/masm-decompiler

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