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High 8.4Published Dec 8, 2025

CVE-2025-66627Wasmi's Linear Memory has a Critical Use After Free Vulnerability

Updated under an hour ago ()

Does this affect you?

It affects wasmi-labs wasmi and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
8.4 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness (CWE)
CWE-416
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Dec 9, 2025
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
wasmi-labs wasmi
wasmi_labs:wasmi (from the name)
from 0.41.0, < 0.41.2; from 0.42.0, < 0.47.1; from 0.50.0, < 0.51.3; from 1.0.0, < 1.0.1
CNA record
wasmi-labs wasmi
wasmi-labs:wasmi
from 0.41.0 before 0.41.2; from 0.47.0 before 0.47.1; from 0.51.0 before 0.51.3; 1.0.0
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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