What’s Vulnerable › Vulnerabilities

CVE-2023-43669: Tungstenite allows remote attackers to cause a denial of service

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.1% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-09-21 · updated 2026-06-17

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 products

• Fedoraproject Fedora: 37, 38, 39
• Snapview Tungstenite: through 0.20.0
• Crates.Io Tungstenite: from 0.0.0-0 before 0.20.1 — fixed in 0.20.1

How to fix

Upgrade to a fixed version: Crates.Io Tungstenite 0.20.1. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=2240110
• https://bugzilla.suse.com/show_bug.cgi?id=1215563
• https://crates.io/crates/tungstenite/versions
• https://cwe.mitre.org/data/definitions/407.html
• https://github.com/advisories/GHSA-9mcr-873m-xcxp
• https://github.com/github/advisory-database/pull/2752
• https://github.com/snapview/tungstenite-rs/commit/8b3ecd3cc0008145ab4bc8d0657c39d09db8c7e2
• https://github.com/snapview/tungstenite-rs/issues/376
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R77EUWPZVP5WSMNXUXUDNHR7G7OI5NGM/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THK6G6CD4VW6RCROWUV2C4HSINKK3XAK/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TT7SF6CQ5VHAGFLWNXY64NFSW4WIWE7D/
• https://security-tracker.debian.org/tracker/CVE-2023-43669

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