EUVD-2025-201826Published

Wasmi's Linear Memory has a Critical Use After Free Vulnerability

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2025-66627

Published

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.

Source published: 9 Dec 2025 02:52:46 UTC
Source modified: 9 Dec 2025 15:21:18 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

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CVSS 3.1 · 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

euvd · EUVD-2025-201826

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Dec 9, 2025, 2:52:46 AM

dateUpdated: Dec 9, 2025, 3:21:18 PM

Source published: Dec 9, 2025, 2:52:46 AM (timezone not stated)
Source modified: Dec 9, 2025, 3:21:18 PM (timezone not stated)
Observed here: 9 Nov 2026 04:09:44 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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EUVD CVSS 3.1 · 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd · CVE-2025-66627

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-416

Original publisher date fields

published: 2025-12-09T16:18:21.910

lastModified: 2026-10-14T21:10:00.183

2 source CPE criteria · context only

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

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 9 Dec 2025 16:18:21 UTC
Source modified: 14 Oct 2026 21:10:00 UTC
Observed here: 25 Oct 2026 03:17:36 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.4 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS 3.1 · [email protected] · Primary · 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

osv · GHSA-g4v2-cjqp-rfmq

Published

### Summary A use-after-free vulnerability has been discovered in the linear memory implementation of Wasmi. This issue can be triggered by a WebAssembly module under certain memory growth conditions, potentially leading to memory corruption, information disclosure, or code execution. ### Impact - **Confidentiality:** High – attacker-controlled memory reads possible. - **Integrity:** High – memory corruption may allow arbitrary writes. - **Availability:** High – interpreter crashes possible. ### Affected Versions Wasmi `v0.41.0` through Wasmi `v1.0.0`. ### Workarounds - Upgrade to the latest patched version of Wasmi. - Consider limiting the maximum linear memory sizes where feasible. ### Credits This vulnerability was discovered by **Robert T. Morris (RTM)**.

Source published: 8 Dec 2025 22:15:49 UTC
Source modified: 10 Sep 2026 03:50:31 UTC
Observed here: 24 Oct 2026 13:19:54 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Publisher rating · HIGH