CVE-2026-34942

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Source
https://cve.org/CVERecord?id=CVE-2026-34942
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34942.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-34942
Aliases
Downstream
Related
Published
2026-04-09T18:32:56.456Z
Modified
2026-07-15T01:49:07.703868927Z
Severity
  • 5.9 (Medium) CVSS_V4 - 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 CVSS Calculator
Summary
Wasmtime panics when transcoding misaligned utf-16 strings
Details

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.

Database specific 
{
    "cwe_ids": [
        "CWE-129"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34942.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/bytecodealliance/wasmtime

Affected ranges

Type
GIT
Repo
https://github.com/bytecodealliance/wasmtime
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
a15daff0bfc965d1656ddcf9beaa1d085c3a7410
Introduced
0b195ef5db76c02fb5392ec1418c58bdc5537d41
Fixed
09539085b9b514b65d5c51e2905dc38f6eb414b9
Introduced
7b3d6ae79e9153a2477668062f5622c10333925f
Fixed
403f9929d4e13ed87c76471d4f4bc8d381c876eb
Introduced
be23469ece57c0be64904f12111c8d808b0ce4ac
Fixed
cd4b6ed9b2a59cd3f317bff812126dd6a0e92dd2
Database specific 
{
    "cpe": "cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "fixed": "24.0.7"
        },
        {
            "introduced": "25.0.0"
        },
        {
            "fixed": "36.0.7"
        },
        {
            "introduced": "37.0.0"
        },
        {
            "fixed": "42.0.2"
        },
        {
            "introduced": "43.0.0"
        },
        {
            "fixed": "43.0.1"
        }
    ],
    "source": "CPE_RANGE"
}

Affected versions

cranelift-v0.*
cranelift-v0.60.0
cranelift-v0.61.0
cranelift-v0.69.0
Other
dev
v0.*
v0.12.0
v0.16.0
v0.17.0
v0.18.0
v0.19.0
v0.20.0
v0.21.0
v0.22.0
v0.23.0
v0.24.0
v0.25.0
v0.26.0
v0.27.0
v0.28.0
v0.29.0
v0.30.0
v0.31.0
v0.32.0
v0.33.0
v0.34.0
v0.35.0
v24.*
v24.0.0
v24.0.1
v24.0.2
v24.0.3
v24.0.4
v24.0.5
v24.0.6
v36.*
v36.0.0
v36.0.1
v36.0.2
v36.0.3
v36.0.4
v36.0.5
v36.0.6
v42.*
v42.0.0
v42.0.1
v43.*
v43.0.0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34942.json"