Wasmtime panics when transcoding misaligned utf-16 strings (bytecodealliance wasmtime)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.35 % · percentile 29 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
Description
Wasmtime is a runtime for WebAssembly. Prior to 24.0.7, 36.0.7, 42.0.2, and 43.0.1, Wasmtime's implementation of transcoding strings into the Component Model's utf16 or latin1+utf16 encodings improperly verified the alignment of reallocated strings. This meant that unaligned pointers could be passed to the host for transcoding which would trigger a host panic. This panic is possible to trigger from malicious guests which transfer very specific strings across components with specific addresses. Host panics are considered a DoS vector in Wasmtime as the panic conditions are controlled by the guest in this situation. This vulnerability is fixed in 24.0.7, 36.0.7, 42.0.2, and 43.0.1.
Weaknesses (CWE)
- CWE-129 — Improper Validation of Array Index
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 5.9 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L | GitHub_M |
| CVSS 4.0 | MEDIUM 5.9 | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | MEDIUM 6.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-20990
- GCVE · GCVE-0-2026-34942
Affected configurations (NVD CPE)
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*< 24.0.7cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*≥ 25.0.0 < 36.0.7cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*≥ 37.0.0 < 42.0.2cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*≥ 43.0.0 < 43.0.1
Affected products
| Product | Versions |
|---|---|
| bytecodealliance · wasmtime | affected < 24.0.7 ; affected >= 25.0.0, < 36.0.7 ; affected >= 37.0.0, < 42.0.2 ; affected >= 43.0.0, < 44.0.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |