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No exploitation reportedFix available

CVE-2021-43790

No exploitation reported by the sources we read.

  • Published2021-11-30
  • WeaknessCWE-416

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2021-11-3000:15CVE publishedNVD

Versions per branch

OSV · NVD
lucet-runtime
BranchAffectedFixed in
0.0+≥ 0.0.0-0no fix published
0.6≤ 0.6.1no fix published
Bytecodealliance lucet
BranchAffectedFixed in
0.6≤ 0.6.1no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.18.5known since 2026-10-23
  • NVDCVSS 3.18.1read 2026-10-23
  • NVDCVSS 2.06.8read 2026-10-23
  • CNAweakness (CWE)CWE-416known since 2026-10-23
  • FIRST EPSSEPSS score1.6 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2021-11-30

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-11-30
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-hf79-8hjp-rrvq

Frequently asked questions

What is CVE-2021-43790?

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.

Is CVE-2021-43790 actively exploited?

Active exploitation of CVE-2021-43790 has not been confirmed. Its EPSS score was 1.6% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43790?

CVE-2021-43790 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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