How severe is CVE-2023-43669?

CVE-2023-43669 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2023-43669?

CVE-2023-43669 affects the following packages: tungstenite (crates.io). Ecosystems affected: crates.io.

How do I fix CVE-2023-43669?

Update tungstenite to 0.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43669 is resolved across your whole dependency graph.

How do I detect CVE-2023-43669 in my crates.io dependencies?

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

How do I mitigate CVE-2023-43669 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2023-43669 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2023-43669, including 1 in-the-wild exploitation observed on GitHub and other sources. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2023-43669?

CVE-2023-43669 has an EPSS (Exploit Prediction Scoring System) score of 2.1%, placing it in the 81th 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-2023-43669 published, and has it been updated?

CVE-2023-43669 was published on September 21, 2023 and was last updated on October 28, 2026. 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

HIGH severity

CVE-2023-43669 — tungstenite

HIGHFix: github/advisory-database#2752

CVE-2023-43669 is a high-severity (CVSS 7.5) vulnerability in tungstenite. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for tungstenite — see the affected versions and patch details below.

Tungstenite allows remote attackers to cause a denial of service

Also known asGHSA-9mcr-873m-xcxpRUSTSEC-2023-0065

Published

Sep 21, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

1 known

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

2.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

🦀tungstenite

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

The Tungstenite crate before 0.20.1 for Rust allows remote attackers to cause a denial of service (minutes of CPU consumption) via an excessive length of an HTTP header in a client handshake. The length affects both how many times a parse is attempted (e.g., thousands of times) and the average amount of data for each parse attempt (e.g., millions of bytes).

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🦀crates.io	`tungstenite`	all versions	0.20.1`cargo update -p tungstenite --precise 0.20.1`

Affected Products

2 products · 4 configurations

fedorafedoraproject

3 versions

373839

Application

tungstenitesnapview

≤ 0.20.0

range

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

The Tungstenite crate before 0.20.1 for Rust allows remote attackers to …

github.comNVDSep 2023

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for tungstenite, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update tungstenite to 0.20.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-43669 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2023-43669 in your dependencies?

Find it across crates.io, including transitive dependencies.

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