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CVE-2020-35859

29
FAUCET Score

CVE-2020-35859 is a critical vulnerability (CVSS 9.1) affecting the lucet-runtime-internals Rust crate prior to version 0.5.1, stemming from improper sigstack allocation. This flaw allows guest programs to potentially access sensitive information or cause memory corruption. The vulnerability is remotely exploitable with low attack complexity, posing a high risk to confidentiality and availability. While there is no evidence of active exploitation or public exploit code, the vulnerability has garnered significant community discussion, indicating awareness within the cybersecurity community.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.5.1CPE matchmatch criteria
cpe:2.3:a:lucet-runtime-internals_project:lucet-runtime-internals:*:*:*:*:*:rust:*:*

CVSS Data

CVSS version used by this source: 3.1

9.1CRITICAL

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.2
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.50%
Probability of exploitation in next 30 days
EPSS Percentile
71.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-26
Model: v2026.06.15
This CVE's current EPSS score of 0.0150 is in the 59th percentile among its peer group of 36,833 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

rustpatch availablevia ghsa
Product: lucet-runtime-internalsFixed in: 0.4.3
rustpatch availablevia ghsa
Product: lucet-runtime-internalsFixed in: 0.5.1

Vendor Advisories (1)

rustGHSA-3933-wvjf-pcvccritical

Out of bounds access in lucet-runtime-internals

Aug 25, 2021

References

rustsec.org / advisories/RUSTSEC-2020-0004.html
PatchThird Party Advisory