What is CVE-2020-35927?

An issue was discovered in the thex crate through 2020-12-08 for Rust. Thex allows cross-thread data races of non-Send types.

How severe is CVE-2020-35927?

CVE-2020-35927 has a CVSS score of 5.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-35927?

CVE-2020-35927 affects the following packages: thex (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2020-35927?

No patched version of thex has shipped for CVE-2020-35927 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

How do I detect CVE-2020-35927 in my crates.io dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for thex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-35927 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Is CVE-2020-35927 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-35927 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-35927?

CVE-2020-35927 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 22th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2020-35927 published, and has it been updated?

CVE-2020-35927 was published on August 25, 2021 and was last updated on November 8, 2023. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🦀

🦀 crates.io

Not in CISA KEV

MEDIUM severity

CVE-2020-35927 — thex

MEDIUM

CVE-2020-35927 is a medium-severity (CVSS 5.5) vulnerability in thex. No vendor fix is recorded yet; mitigation options are listed below.

Data races in thex

Also known asRUSTSEC-2020-0090

Published

Aug 25, 2021

Updated

Nov 8, 2023

Affected

1 pkg

Patched

See advisory

Exploits

None indexed

Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs22th percentile — riskier than 22% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2020-35927 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,386 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🦀thex

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects crates.io packages — download data is not available via public APIs for these ecosystems.

Description

An issue was discovered in the thex crate through 2020-12-08 for Rust. Thex<T> allows cross-thread data races of non-Send types.

Affected Packages

1 total

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`thex`	all versions	No fix

Affected Products

1 product · 1 configurations

Application

thexthex_project

≤ 2020-12-08

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for thex, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of thex has shipped for CVE-2020-35927 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

Frequently Asked Questions

An issue was discovered in the thex crate through 2020-12-08 for Rust. Thex<T> allows cross-thread data races of non-Send types.

O3 Security · Impact-Aware SCA

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