lean-cve-poc

CVE-2026-72844: Lean 4 Kernel Soundness Bug Proving0 = 1 axiom-free via nested inductive projection validation bypass. Field| Value ---|--- CVE| CVE-2026-72844 Advisory| VulnCheck VCSA Bug report| leanprover/lean414576 Fix| leanprover/lean414577 Affected| Lean 4 ≤ v4.31.0 / nightly ≤ 2026-07-27...

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Lean 4 version 4.31.0 and earlier contain a kernel soundness vulnerability caused by improper validation of opaque declarations and stale free-variable inference-cache entries. A malicious metaprogram can exploit the missing closure check in the addopaque path to register an opaque constant of ty...

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Rocq Prover versions up to and including 9.2.0 contain a kernel soundness vulnerability in the termination guard checker. Recursive functions involving type transport through the rew construct can corrupt the internal recursive argument tree representation, allowing subsequent fixpoints to be...

CVE-2026-72711 Lean 4 before 4.32.2 Kernel Accepts Opaque Declaration With an Unbound Free Variable

The Lean 4 kernel does not check that the body of an opaque declaration is closed. environment::addopaque omits the checknometavarnofvar call that the definition and theorem paths perform, so a value containing a free variable that is absent from the local context is not rejected outright. A...

CVE-2026-72844 Lean 4 Kernel Type Checking Bypass via Mismatched Structure Projections

The Lean 4 kernel does not verify that the structure named in a projection expression matches the type of the value being projected, and environment::addinductive in src/kernel/inductive.cpp did not type check the nested inductive applications that are replaced by auxiliary types, so their...