---
id: CVE-2023-43669
aliases:
  - GHSA-9mcr-873m-xcxp
  - RUSTSEC-2023-0065
title: Tungstenite allows remote attackers to cause a denial of service
summary: Tungstenite allows remote attackers to cause a denial of service
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
vendor: tungstenite
product: tungstenite
ecosystem: rust
affected:
  - tungstenite < 0.20.1
patched:
  - tungstenite 0.20.1
published: '2023-09-21'
updated: '2026-07-08'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-9mcr-873m-xcxp'
references:
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2023-43669'
  - url: 'https://github.com/snapview/tungstenite-rs/issues/376'
  - url: 'https://github.com/github/advisory-database/pull/2752'
  - url: 'https://github.com/snapview/tungstenite-rs/pull/379'
  - url: >-
      https://github.com/snapview/tungstenite-rs/commit/8b3ecd3cc0008145ab4bc8d0657c39d09db8c7e2
  - url: 'https://security-tracker.debian.org/tracker/CVE-2023-43669'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2023-0065.html'
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TT7SF6CQ5VHAGFLWNXY64NFSW4WIWE7D
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/THK6G6CD4VW6RCROWUV2C4HSINKK3XAK
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/R77EUWPZVP5WSMNXUXUDNHR7G7OI5NGM
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TT7SF6CQ5VHAGFLWNXY64NFSW4WIWE7D
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/THK6G6CD4VW6RCROWUV2C4HSINKK3XAK
  - url: >-
      https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R77EUWPZVP5WSMNXUXUDNHR7G7OI5NGM
  - url: 'https://github.com/snapview/tungstenite-rs'
  - url: 'https://github.com/advisories/GHSA-9mcr-873m-xcxp'
  - url: 'https://cwe.mitre.org/data/definitions/407.html'
  - url: 'https://crates.io/crates/tungstenite/versions'
  - url: 'https://bugzilla.suse.com/show_bug.cgi?id=1215563'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2240110'
tags:
  - osv
  - rust
epss: 0.02057
epssPercentile: 0.80481
ingestedAt: '2026-07-09T18:56:37.294Z'
---

## Overview

The Tungstenite crate through 0.20.0 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

- `tungstenite < 0.20.1`

## Remediation

Upgrade to a patched release:

- `tungstenite 0.20.1`