---
title: "CVE-2026-54466: websocket-driver: Message corruption via abuse of protocol length headers"
url: https://erroneo.us/security/cve/CVE-2026-54466/
description: "CVE-2026-54466 (websocket-driver (npm)): websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-07-17
date_modified: 2026-07-20
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-54466"
kev: false
cvss: 9.2
epss: 0.0038
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-54466: websocket-driver: Message corruption via abuse of protocol length headers

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.4% , percentile 31: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 31% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes websocket-driver (npm) < 0.7.5, fixed in 0.7.5 . Check your lockfile, including transitive dependencies.

## What it is

websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.

## Affected packages

- npm `websocket-driver` < 0.7.5 → fixed: 0.7.5

## Affected products (CVE record)

- faye websocket-driver-node: < 0.7.5

## Severity

- GitHub_M CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.38% probability of exploitation activity in the next 30 days; percentile 31.

## Sources

- [GitHub Advisory GHSA-xv26-6w52-cph6](https://github.com/advisories/GHSA-xv26-6w52-cph6)
- [CVE.org record CVE-2026-54466](https://www.cve.org/CVERecord?id=CVE-2026-54466)
- [NVD entry CVE-2026-54466](https://nvd.nist.gov/vuln/detail/CVE-2026-54466)
- [github.com](https://github.com/faye/websocket-driver-node/security/advisories/GHSA-xv26-6w52-cph6)
- [github.com](https://github.com/faye/websocket-driver-node/commit/5b197ca874dab58e96cacad8a3c256797d804680)
- [github.com](https://github.com/faye/websocket-driver-node/releases/tag/0.7.5)

---
Source page: https://erroneo.us/security/cve/CVE-2026-54466/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt