CVE-2025-66627 json
Wasmi's Linear Memory has a Critical Use After Free Vulnerability
published 11mo ago modified 26d ago also EUVD-2025-201826 , GHSA-g4v2-cjqp-rfmq
- cvss
- 8.4
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 4%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- crates.io wasmi 0.41.2, 0.47.1, 0.51.3, 1.0.1
- wasmi-labs wasmi 0.41.2, 0.47.1, 0.51.3, 1.0.1
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Check with FencerCISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- total
- Assessed
- 11mo ago
Exploit prediction
0.16% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 8.4 | CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | wasmi | >=0.41.0, <0.41.2 >=0.42.0, <0.47.1 >=0.50.0, <0.51.3 >=1.0.0, <1.0.1 |
0.41.2 0.47.1 0.51.3 1.0.1 |
Affected products
- wasmi-labs wasmi
Classification
- Weakness
-
- CWE-416 Use After Free
References
Sources
- CVE List CVE-2025-66627
- GitHub Advisory GHSA-g4v2-cjqp-rfmq
- NVD CVE-2025-66627
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.