CVE-2020-35859: An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust

Q: How do I fix CVE-2020-35859?

lucet-runtime-internals: upgrade to 0.5.1. Exact commands for each OS are on this page.

Q: Is CVE-2020-35859 being exploited?

CVE-2020-35859 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-35859 affect?

CVE-2020-35859 affects lucet-runtime-internals. Severity is critical (CVSS 9.1). An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.

Q: How urgent is CVE-2020-35859?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2020-35859 is a critical-severity flaw (CVSS 9.1) affecting lucet-runtime-internals. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.5% (top 25%)
CISA exploited list	No
Weakness	CWE-125, CWE-787
Published	2020-12-31
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: lucet-runtime-internals project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-12-31 10:15 UTCPublished CVE record published
2026-06-17 03:14 UTCUpdated Record last modified

lucet-runtime-internals project lucet-runtime-internals UPGRADE

Affected: < 0.5.1

Fixed in: 0.5.1

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy lucet-runtime-internals || rpm -q lucet-runtime-internals || lucet-runtime-internals --version

2. UPGRADE to 0.5.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade lucet-runtime-internals

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade lucet-runtime-internals

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-35859?

lucet-runtime-internals: upgrade to 0.5.1. Exact commands for each OS are on this page.

Is CVE-2020-35859 being exploited?

CVE-2020-35859 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-35859 affect?

CVE-2020-35859 affects lucet-runtime-internals. Severity is critical (CVSS 9.1). An issue was discovered in the lucet-runtime-internals crate before 0.5.1 for Rust. It mishandles sigstack allocation. Guest programs may be able to obtain sensitive information, or guest programs can experience memory corruption.

How urgent is CVE-2020-35859?

Priority 56/100. Critical severity; Remotely exploitable, no login, no user action

References

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