RISC Zero zkVM Underconstrained Vulnerability
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- None · Low · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-345.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| risc0 | risc0 | 2.0.0 to before 2.1.0 | 2.1.0 | Patch available | CNA |
| — | risc0-zkvm (crates.io) | 2.0.0 to before 2.1.0 | 2.1.0 | Patch available | GHSA-g3qg-6746-3mg9 |
| — | risc0-circuit-rv32im (crates.io) | 2.0.0 to before 2.0.4 | 2.0.4 | Patch available | GHSA-g3qg-6746-3mg9 |
- risc0 Vendorrisc0 Affected 2.0.0 to before 2.1.0 Fixed in 2.1.0 Patch available CNA
- risc0-zkvm (crates.io) Vendor— Affected 2.0.0 to before 2.1.0 Fixed in 2.1.0 Patch available GHSA-g3qg-6746-3mg9
- risc0-circuit-rv32im (crates.io) Vendor— Affected 2.0.0 to before 2.0.4 Fixed in 2.0.4 Patch available GHSA-g3qg-6746-3mg9
Remediation
- Fix · CNA risc0 (risc0) Fixed in 2.1.0
- Fix · GHSA-g3qg-6746-3mg9 risc0-zkvm (crates.io) Fixed in 2.1.0 Advisory →
- Fix · GHSA-g3qg-6746-3mg9 risc0-circuit-rv32im (crates.io) Fixed in 2.0.4 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2025-52484
- 2026-10-03 Alias added: GHSA-g3qg-6746-3mg9
References
Other 8
- 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
- https://github.com/risc0/risc0
More risc0 vulnerabilities
- TI-2025-38034 risc0 vulnerable to arbitrary code execution in guest via memory safety failure in `sys_read` CVSS 4.0CRITICAL 9.3
- TI-2025-32920 risc0-ethereum-contracts allows invalid commitment with digest value of zero to be accepted by Steel.validateCommitment CVSS 4.0LOW 1.7
- TI-2025-34607 RISC Zero Underconstrained Vulnerability: Division CVSS 4.0LOW 2.7
Sources
- CVE-2025-52484 · CVE Program
- CVE-2025-52484 · NVD
- FIRST EPSS
- GHSA-g3qg-6746-3mg9 · GitHub Advisory Database · CC BY 4.0
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