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

> An attacker can cause message corruption and potential service disruption by sending malformed WebSocket frames with excessively large length headers.

- **Severity:** Critical 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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Jul 2026
- **Updated:** 20 Jul 2026
- **Also known as:** CLEANSTART-2026-BN70978, CLEANSTART-2026-MI43337, CLEANSTART-2026-SA59159, DEBIAN-CVE-2026-54466, GHSA-xv26-6w52-cph6, MINI-343j-83v7-w4rf, MINI-4pvg-hp8j-62hg, MINI-576x-mghc-vwvv, MINI-5jh7-x63f-mrmx, MINI-7r67-mqjh-rg2j, MINI-83ww-5qpc-mhfv, MINI-c29r-pqp8-rp99, MINI-c9jm-3c57-66c4, OESA-2026-3212, ROOT-APP-NPM-CVE-2026-54466, UBUNTU-CVE-2026-54466

## What is CVE-2026-54466?

CVE-2026-54466 is a critical denial of service vulnerability in faye websocket-driver-node, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-130 (Improper Handling of Length Parameter Inconsistency)

## Which versions are affected by CVE-2026-54466?

2 open source packages ship an affected version, including websocket-driver. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `websocket-driver` | npm | All versions | 0.7.5 |
| `websocket-driver` | npm | All versions | 0.7.5 |

Products: Faye Websocket-Driver.

## How do I fix CVE-2026-54466?

Upgrade websocket-driver to 0.7.5 or later.

## Is CVE-2026-54466 being exploited?

There is no known exploitation of CVE-2026-54466 in the wild and no public exploit code.

## Other vulnerabilities in faye websocket-driver-node

- [CVE-2026-54463](https://insights.sbomify.com/CVE-2026-54463/): websocket-driver: Memory exhaustion via abuse of protocol length headers (medium 6.9)
- [CVE-2026-54465](https://insights.sbomify.com/CVE-2026-54465/): websocket-driver: Memory exhaustion in HTTP header parser (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-54466 and fix it if it is affected.

What it is: CVE-2026-54466 is a critical denial of service vulnerability in faye websocket-driver-node, published on 17 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-54466 in the wild and no public exploit code.

Affected packages and fixed versions:
- websocket-driver (npm): affected all versions; fixed in 0.7.5
- websocket-driver (npm): affected all versions; fixed in 0.7.5

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-54466/ (Markdown: https://insights.sbomify.com/CVE-2026-54466/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-54466
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-54466
- OSV: https://osv.dev/vulnerability/CVE-2026-54466

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-54466/
Summaries are generated and may contain mistakes; the official description above is the record.