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🦀 crates.io
Not in CISA KEV
HIGH severity

CVE-2020-35896

HIGH

CVE-2020-35896 is a high-severity (CVSS 7.5) CWE-770 vulnerability in ws. O3 Security confirms whether CVE-2020-35896 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Insufficient size checks in ws

Also known asGHSA-rh7x-ppxx-p34cRUSTSEC-2020-0043
Published
Dec 31, 2020
Updated
Jul 9, 2026
Affected
1 pkg
Patched
None yet
Exploits
None indexed
Exploitation data as of Jul 9, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected
🦀ws

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 ws crate through 2020-09-25 for Rust. The outgoing buffer is not properly limited, leading to a remote memory-consumption attack.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
🦀crates.iowsall versionsNo fix

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for ws. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Remediation status

    No patched version of ws has shipped for CVE-2020-35896 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.

  3. 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.

  4. How O3 protects you

    O3 pinpoints whether CVE-2020-35896 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2020-35896. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

An issue was discovered in the ws crate through 2020-09-25 for Rust. The outgoing buffer is not properly limited, leading to a remote memory-consumption attack.
O3 Security · Impact-Aware SCA

Is CVE-2020-35896 in your dependencies?

O3 detects CVE-2020-35896 across crates.io dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

CVE-2020-35896: Insufficient size checks in… | O3 Security