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...

CVE-2026-72711

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-2026-72711 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...

EUVD-2026-65142

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-2026-72711

CVE-2026-72711 is a kernel soundness flaw in Lean 4 before 4.32.2. The function environment::add_opaque omits the check_no_metavar_no_fvar closure check that the definition and theorem paths perform. A metaprogram can exploit a stale entry in the type checker's inference cache to submit an opaque...

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-2026-72711 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...

PT-2026-81020

The Lean 4 kernel does not check that the body of an opaque declaration is closed. environment::add opaque omits the check no metavar no fvar 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-2026-72711: Improper Input Validation

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

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...

EUVD-2026-63487

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...

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...

CVE-2026-72844

CVE-2026-72844 is a kernel soundness break in Lean 4 , the theorem prover. The root cause is a missing type check in environment::add_inductive (src/kernel/inductive.cpp): nested inductive applications replaced by auxiliary types had their parametric arguments unchecked, and the kernel did not ve...

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...

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...

CVE-2026-72844: Access of Resource Using Incompatible Type

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...

PT-2026-79074

Name of the Vulnerable Software and Affected Versions Lean 4 affected versions not specified Description The kernel fails to verify that the structure named in a projection expression matches the type of the value being projected. Additionally, the environment::add inductive function in...

CVE-2026-32732: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS)

Lean 4 VS Code Extension is a Visual Studio Code extension for the Lean 4 proof assistant. Projects that use @leanprover/unicode-input-component are vulnerable to an XSS exploit in 0.1.9 of the package and lower. The component re-inserted text in the input element back into the input element as...

Lean 4 VS Code Extension 安全漏洞

Lean 4 VS Code Extension is an open-source extension for VS Code. Versions of Lean 4 VS Code Extension 0.1.9 and earlier contain security vulnerabilities. These vulnerabilities stem from the @leanprover/unicode-input-component component reinserting text from input elements as unescaped HTML, whic...