Security advisory
Lucet is a native WebAssembly compiler and runtime. There is a bug in the main branch of `lucet-runtime` affecting all versions published to crates.io that allows a use-after-free in an Instance object that could result in memory corruption, data race, or other related issues. This bug was introduced early in the development of Lucet and is present in all releases. As a result of this bug, and dependent on the memory backing for the Instance objects, it is possible to trigger a use-after-free when the Instance is dropped. Users should upgrade to the main branch of the Lucet repository. Lucet no longer provides versioned releases on crates.io. There is no way to remediate this vulnerability without upgrading.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2021-43790
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 12:00 UTC · Revision 1
Source evidence
Lucet is a native WebAssembly compiler and runtime. There is a bug in the main branch of `lucet-runtime` affecting all versions published to crates.io that allows a use-after-free in an Instance object that could result in memory corruption, data race, or other related issues. This bug was introduced early in the development of Lucet and is present in all releases. As a result of this bug, and dependent on the memory backing for the Instance objects, it is possible to trigger a use-after-free when the Instance is dropped. Users should upgrade to the main branch of the Lucet repository. Lucet no longer provides versioned releases on crates.io. There is no way to remediate this vulnerability without upgrading.
osv:CVE-2021-43790
Complete source record
{
"id": "7901c8c2b2a94cc300fc8dcca870f7fbb1d014dd6310c32d9f36bec0cbd9a685",
"url": "https://osv.dev/vulnerability/CVE-2021-43790",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2021-43790",
"summary": "Lucet is a native WebAssembly compiler and runtime. There is a bug in the main branch of `lucet-runtime` affecting all versions published to crates.io that allows a use-after-free in an Instance object that could result in memory corruption, data race, or other related issues. This bug was introduced early in the development of Lucet and is present in all releases. As a result of this bug, and dependent on the memory backing for the Instance objects, it is possible to trigger a use-after-free when the Instance is dropped. Users should upgrade to the main branch of the Lucet repository. Lucet no longer provides versioned releases on crates.io. There is no way to remediate this vulnerability without upgrading.",
"evidence": "osv:CVE-2021-43790",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2021-43790",
"aliases": [
"CVE-2021-43790",
"GHSA-hf79-8hjp-rrvq",
"RUSTSEC-2021-0155"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/bytecodealliance/lucet",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"last_affected": "0914a54f9b5ff557d4e497787d659183304dd9f8"
},
{
"fixed": "7c7757c772fb709c61b1442bcc1e1fbee97bf4a8"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:bytecodealliance:lucet:*:*:*:*:*:rust:*:*",
"range": [
{
"introduced": "0"
},
{
"last_affected": "0.6.1"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "7c7757c772fb709c61b1442bcc1e1fbee97bf4a8"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"0.6.1",
"0.5.1",
"0.5.0",
"0.4.1",
"0.3.1",
"0.3.0",
"0.2.2",
"0.2.1",
"0.1.1",
"0.2.0",
"before-deleting-c-runtime"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43790.json"
}
}
],
"modified": "2026-10-20T10:55:03.872578344Z",
"provider": "osv",
"references": [
"https://crates.io/crates/lucet-runtime",
"https://github.com/bytecodealliance/lucet/commit/7c7757c772fb709c61b1442bcc1e1fbee97bf4a8",
"https://github.com/bytecodealliance/lucet/security/advisories/GHSA-hf79-8hjp-rrvq"
],
"provider_metadata": {}
},
"related_cves": [
{
"value": "CVE-2021-43790",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 386815,
"published_at": "2021-11-30T00:15:07.357+00:00"
}