CVE-2026-72704 Rocq Prover through 9.2.0 Guard Checker Trusts Corrupted Recursive Tree After Transport
Attackers can exploit a guard checker flaw in Rocq Prover to prove False, enabling arbitrary code execution or logical contradictions in verified software.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-72704?
CVE-2026-72704 is a medium-severity vulnerability in rocq-prover rocq, published on 24 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
The guard checker in Rocq Prover does not recheck the recursive tree representation of an inductive type parameter after that parameter has been changed by transport. A fixpoint may apply a rewrite along an equality between types to its recursive argument, which the guard checker accepts because the inductive type is preserved, while the recursive tree recorded for the parameter is altered. A second fixpoint that calls the first inherits the altered recursive tree without verification, so a call that is not structurally decreasing is accepted as terminating. The resulting non-terminating definition proves that a natural number equals its own successor and therefore False, from which any proposition follows. The demonstration uses two axioms that follow from univalence and are consistent with the calculus of inductive constructions, so the contradiction comes from the guard check rather than from the assumptions. A fix is proposed but not merged.
Weakness: CWE-670
Which versions are affected by CVE-2026-72704?
How do I fix CVE-2026-72704?
No fix has been published for CVE-2026-72704 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-72704 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-72704 exists.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-h294-vvmw-mqg3.