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CVE-2021-43790

26
FAUCET Score

CVE-2021-43790 is a high-severity use-after-free vulnerability (CWE-416) affecting all versions of the Lucet native WebAssembly compiler and runtime published to crates.io. This flaw allows for memory corruption, data races, or other issues when an Instance object is dropped, potentially leading to a complete compromise of confidentiality, integrity, and availability. With a CVSS score of 8.1, this network-exploitable vulnerability has high impact and high attack complexity, requiring users to upgrade to the main branch of the Lucet repository for remediation. There is currently no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
<= 0.6.1CPE matchmatch criteria
cpe:2.3:a:bytecodealliance:lucet:*:*:*:*:*:rust:*:*

CVSS Data

CVSS version used by this source: 3.1

8.5HIGH

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.57%
Probability of exploitation in next 30 days
EPSS Percentile
72.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0157 is in the 30th percentile among its peer group of 8,915 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

Vendor Advisories (1)

rustGHSA-hf79-8hjp-rrvqhigh

Use After Free in lucet

Nov 30, 2021

References

crates.io / crates/lucet-runtime
ProductThird Party Advisory
github.com / bytecodealliance/lucet/commit/7c7757c772fb709c61b1442bcc1e1fbee97bf4a8
PatchThird Party Advisory
github.com / bytecodealliance/lucet/security/advisories/GHSA-hf79-8hjp-rrvq
ExploitThird Party Advisory