Summary
zkVM Underconstrained Vulnerability
Due to a missing constraint in the rv32im circuit, any 3-register RISC-V instruction (including remu and divu) in risc0-zkvm 2.0.0, 2.0.1, and 2.0.2 are vulnerable to an attack by a malicious prover. The main idea for the attack is to confuse the RISC-V virtual machine into treating the value of the rs1 register as the same as the rs2 register due to a lack of constraints in the rv32im circuit.
This vulnerability was reported by Christoph Hochrainer via our Hackenproof bug bounty. We have evaluated the severity of the vulnerability as “Critical,” and paid a bounty.
The fix for the circuit was implemented in zirgen/pull/238, and the update to risc0 was implemented in risc0/pull/3181. Impacted on-chain verifiers have already been disabled via the estop mechanism outlined in the Verifier Management Design.
Mitigation
We recommend all impacted users upgrade as soon as possible.
Rust applications using the risc0-zkvm crate at versions 2.0.0, 2.0.1, and 2.0.2 should upgrade to version 2.1.0.
Smart contract applications using the official RISC Zero Verifier Router do not need to take any action: zkVM version 2.1 is active on all official routers, and version 2.0 has been disabled.
Smart contract applications not using the verifier router should update their contracts to send verification calls to the 2.1 version of the verifier.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
risc0-zkvm to 2.1.0 or later; risc0-circuit-rv32im to 2.0.4 or later
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2025-52484? CVE-2025-52484 is a low-severity security vulnerability in risc0-zkvm (rust), affecting versions >= 2.0.0, <= 2.0.2. It is fixed in 2.1.0, 2.0.4.
- Which packages are affected by CVE-2025-52484?
risc0-zkvm(rust) (versions >= 2.0.0, <= 2.0.2)risc0-circuit-rv32im(rust) (versions >= 2.0.0, <= 2.0.3)
- Is there a fix for CVE-2025-52484? Yes. CVE-2025-52484 is fixed in 2.1.0, 2.0.4. Upgrade to this version or later.
- Is CVE-2025-52484 exploitable, and should I be worried? Whether CVE-2025-52484 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-52484 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2025-52484?
- Upgrade
risc0-zkvmto 2.1.0 or later - Upgrade
risc0-circuit-rv32imto 2.0.4 or later
- Upgrade