Use After Free in Wasmi-Labs Wasmi
CVE-2025-66627
Wasmi is a WebAssembly interpreter focused on constrained and embedded systems. In versions 0.41.0, 0.41.1, 0.42.0 through 0.47.1, 0.50.0 through 0.51.2 and 1.0.0, Wasmi's linear memory implementation leads to a Use After Free vulnerability, triggered by a WebAssembly module under certain memory growth conditions. This issue potentially leads to memory corruption, information disclosure, or code execution. This issue is fixed in versions 0.41.2, 0.47.1, 0.51.3 and 1.0.1. To workaround this issue, consider limiting the maximum linear memory sizes where feasible.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.4 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (3.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
- Wasmi-Labs Wasmi — versions >= 0.42.0, < 0.47.1, 1.0.0, >= 0.41.0, < 0.41.2
Weakness classification (CWE)
References
- github.com/wasmi-labs/wasmi/security/advisories/GHSA-g4v2-cjqp-rfmq (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-66627?
- CVE-2025-66627 is a high-severity vulnerability in Wasmi-Labs Wasmi, classified under Use After Free. CVSS score: 8.4/10. Published 2025-12-09.
- How severe is CVE-2025-66627?
- High severity. CVSS v3 base score is 8.4 out of 10.