How severe is CVE-2025-66627?

CVE-2025-66627 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-66627 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-66627?

CVE-2025-66627 primarily affects Wasmi-labs Wasmi. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-66627?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-66627 have an EU (EUVD) identifier?

Yes. CVE-2025-66627 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201826.

When was CVE-2025-66627 published?

CVE-2025-66627 was published on 2025-12-09 and last updated on 2026-06-17.

CVE-2025-66627

CVE-2025-66627 is a high-severity vulnerability in Wasmi-labs Wasmi with a CVSS 3.x base score of 8.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-416.

Key facts

Severity: High (CVSS 3.x base score 8.4)
EPSS exploit prediction: 0% (3rd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-201826
Weakness: CWE-416
Affected product: Wasmi-labs Wasmi
Published: 2025-12-09
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2025-66627?: CVE-2025-66627 has a CVSS 3.x base score of 8.4, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-66627 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (3rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-66627?: CVE-2025-66627 primarily affects Wasmi-labs Wasmi. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-66627?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-66627 have an EU (EUVD) identifier?: Yes. CVE-2025-66627 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-201826.
When was CVE-2025-66627 published?: CVE-2025-66627 was published on 2025-12-09 and last updated on 2026-06-17.

References

https://github.com/wasmi-labs/wasmi/security/advisories/GHSA-g4v2-cjqp-rfmq

Affected products (2)

cpe:2.3:a:wasmi-labs:wasmi:*:*:*:*:*:rust:*:*
cpe:2.3:a:wasmi-labs:wasmi:1.0.0:*:*:*:*:rust:*:*

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