CVE-2021-43790 json
Use After Free in lucet
published 2021-11-29 4 y ago modified 2026-10-12 27 d ago also GHSA-hf79-8hjp-rrvq , RUSTSEC-2021-0155 , EUVD-2021-2355
- cvss
- 8.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 1.6%
- EPSS 1.6% chance of exploitation in 30 days, percentile 76%
- public exploits
- 0
- none known
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.
Patch / fix
Exploit prediction
1.62% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/bytecodealliance/lucet/security/advisories/GHSA-hf79-8hjp-rrvq referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| NVD | 3.1 | 8.1 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 6.8 | AV:N/AC:M/Au:N/C:P/I:P/A:P |
| GitHub | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
| OSV | 3.1 | 8.5 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| crates.io | lucet-runtime | <=0.6.1 >=0.0.0-0 |
no fix listed |
Affected products
- bytecodealliance lucet
Classification
- Weakness
-
- CWE-416 Use After Free
References
-
github.com
/bytecodealliance/lucet/commit/7c7757c772fb709c61b1442bcc1e1fbee97bf4a8
web, patch, third-party-advisory
-
github.com
/bytecodealliance/lucet/security/advisories/GHSA-hf79-8hjp-rrvq
web, exploit, third-party-advisory
-
crates.io
/crates/lucet-runtime
web, product, third-party-advisory, package
-
nvd.nist.gov
/vuln/detail/CVE-2021-43790
advisory
-
github.com
/bytecodealliance/lucet
package
-
rustsec.org
/advisories/RUSTSEC-2021-0155.html
web, advisory
Sources
- CVE List CVE-2021-43790
- GitHub Advisory GHSA-hf79-8hjp-rrvq
- NVD CVE-2021-43790
- OSV RUSTSEC-2021-0155
Fencer Vulns 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.