CVE-2021-43790

HIGHNVD 8.58.5—
EchelonGraph scoreMEDIUM confidence

Score 8.5 from GitHub Security Advisory (severity: HIGH) published 2021-11-30. NVD baseline CVSS 8.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
8.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.6%CVSS: 8.5Exploit: None knownExposed services: Not assessed

A fixed version is listed under Patch Availability — apply it.

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.

CVSS v3
8.5
EG Score
8.5HIGHmedium confidence
EG Risk
43
EG Risk 43/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity85% × 45%
Exploitation2% × 40%
Automatability30% × 15%
CISA SSVC: Track at low or medium mission impact; Track or Attend at high (mission-essential systems).
Action: A fixed version is listed under Patch Availability. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
1.6%
EPSS %ILE
75th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track or Attend at high (mission-essential systems).

A fixed version is listed under Patch Availability. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (no KEV listing, exploit record or EPSS ≥ 50%) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

November 30, 2021

Last Modified

November 21, 2024

Advisory Details (3)

Auto-updated Sep 2, 2026
Fixed version listed under Patch Availability. Sources: github_commit, github.
githubMentions a patch (unverified)

Use After Free in lucet-runtime · Advisory · bytecodealliance/lucet · GitHub

https://github.com/bytecodealliance/lucet/security/advisories/GHSA-hf79-8hjp-rrvq
github_commit

commit 7c7757c772fb (bytecodealliance/lucet)

Fix landed in bytecodealliance/lucet commit 7c7757c772fb — awaiting tagged release

https://github.com/bytecodealliance/lucet/commit/7c7757c772fb709c61b1442bcc1e1fbee97bf4a8
generic

crates.io: Rust Package Registry

https://crates.io/crates/lucet-runtime

Patch Availability(1)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
rustlucet-runtime—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(1 across 1 ecosystem)
crates.io(1)
PackageVulnerable rangeFix by version rangeDependents
lucet-runtime—
  • every version through 0.6.1: no fix on record
  • 0.0.0-0 on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 32× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 189 total refreshes for this CVE.

  1. 2026-10-10 19:56 UTCEPSS rescore
  2. 2026-10-09 20:04 UTCEPSS rescore
  3. 2026-10-08 16:40 UTCEPSS rescore
  4. 2026-10-07 23:45 UTCEPSS rescore
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  10. 2026-10-01 19:46 UTCEPSS rescore
  11. 2026-09-30 15:43 UTCEG score recompute
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  14. 2026-09-28 13:47 UTCEPSS rescore
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  17. 2026-09-26 00:21 UTCEPSS rescore
  18. 2026-09-25 12:05 UTCOSV refresh
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  21. 2026-09-23 13:44 UTCEPSS rescore
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  23. 2026-09-21 20:28 UTCEPSS rescore
  24. 2026-09-19 15:38 UTCEPSS rescore
  25. 2026-09-18 19:23 UTCEPSS rescore
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  1. 2026-09-17 19:23 UTCEPSS rescore
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  3. 2026-09-16 14:05 UTCEPSS rescore
  4. 2026-09-15 03:06 UTCEPSS rescore
  5. 2026-09-12 14:57 UTCEPSS rescore
  6. 2026-09-11 14:49 UTCEPSS rescore
  7. 2026-09-11 09:33 UTCEPSS rescore
  8. 2026-09-08 21:56 UTCEPSS rescore
  9. 2026-09-07 15:58 UTCEPSS rescore
  10. 2026-09-06 13:45 UTCEPSS rescore
  11. 2026-09-06 03:00 UTCOSV refresh
  12. 2026-09-05 15:25 UTCEPSS rescore
  13. 2026-09-04 13:57 UTCEPSS rescore
  14. 2026-09-04 05:03 UTCEPSS rescore
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  18. 2026-08-30 19:14 UTCEPSS rescore
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  20. 2026-08-30 01:19 UTCEPSS rescore
  21. 2026-08-28 21:37 UTCEPSS rescore
  22. 2026-08-27 14:22 UTCEPSS rescore
  23. 2026-08-26 14:43 UTCEPSS rescore
  24. 2026-08-25 13:46 UTCEPSS rescore
  25. 2026-08-24 14:13 UTCEPSS rescore
  26. 2026-08-23 00:16 UTCEPSS rescore
  27. 2026-08-21 23:46 UTCEPSS rescore
  28. 2026-08-20 22:52 UTCEPSS rescore
  29. 2026-08-20 22:52 UTCEPSS rescore
  30. 2026-08-19 17:01 UTCEPSS rescore
  31. 2026-08-19 14:02 UTCOSV refresh
  32. 2026-08-18 13:45 UTCEPSS rescore
  33. 2026-08-17 13:44 UTCEPSS rescore
  34. 2026-08-16 14:53 UTCEPSS rescore
  35. 2026-08-16 02:11 UTCEPSS rescore
  36. 2026-08-15 01:27 UTCEPSS rescore
  37. 2026-08-13 21:57 UTCEPSS rescore
  38. 2026-08-12 13:48 UTCEPSS rescore
  39. 2026-08-11 13:38 UTCEPSS rescore
  40. 2026-08-09 13:44 UTCEPSS rescore
  41. 2026-08-08 16:33 UTCEPSS rescore
  42. 2026-08-07 16:24 UTCEPSS rescore
  43. 2026-08-06 13:44 UTCEPSS rescore
  44. 2026-08-05 19:14 UTCEPSS rescore
  45. 2026-08-04 10:34 UTCEPSS rescore
  46. 2026-08-04 09:57 UTCOSV refresh
  47. 2026-08-03 10:33 UTCEPSS rescore
  48. 2026-08-02 02:24 UTCEPSS rescore
  49. 2026-08-01 04:13 UTCEPSS rescore
  50. 2026-07-30 16:25 UTCEPSS rescore
  51. 2026-07-30 01:28 UTCEPSS rescore
  52. 2026-07-28 15:33 UTCEPSS rescore
  53. 2026-07-26 14:52 UTCEPSS rescore
  54. 2026-07-26 14:52 UTCEPSS rescore
  55. 2026-07-25 14:15 UTCEPSS rescore
  56. 2026-07-24 14:15 UTCEPSS rescore
  57. 2026-07-23 14:16 UTCEPSS rescore
  58. 2026-07-23 02:05 UTCEG score recompute
  59. 2026-07-22 22:51 UTCEG score recompute
  60. 2026-07-22 14:06 UTCEPSS rescore
  61. 2026-07-21 15:22 UTCEPSS rescore
  62. 2026-07-21 15:22 UTCEPSS rescore
  63. 2026-07-20 17:05 UTCEPSS rescore
  64. 2026-07-19 14:29 UTCEPSS rescore
  65. 2026-07-19 02:27 UTCEPSS rescore
  66. 2026-07-18 10:02 UTCEPSS rescore
  67. 2026-07-18 10:02 UTCEPSS rescore
  68. 2026-07-18 07:29 UTCOSV refresh
  69. 2026-07-16 17:00 UTCEPSS rescore
  70. 2026-07-16 17:00 UTCEPSS rescore
  71. 2026-07-15 16:55 UTCEPSS rescore
  72. 2026-07-15 16:55 UTCEPSS rescore
  73. 2026-07-15 01:58 UTCEPSS rescore
  74. 2026-07-13 22:27 UTCEPSS rescore
  75. 2026-07-13 22:27 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2021-43790?
CVE-2021-43790 is a high vulnerability published on November 30, 2021. 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…
When was CVE-2021-43790 disclosed?
CVE-2021-43790 was first published on November 30, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2021-43790 actively exploited?
CVE-2021-43790 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.6% probability of exploitation in the next 30 days (75th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-43790?
CVE-2021-43790 has a CVSS v3 base score of 8.5 (NVD).
How do I remediate CVE-2021-43790?
A fixed version for CVE-2021-43790 is listed under Patch Availability on this page: update to the version listed for your package.

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