CVE-2026-54463 websocket-driver: Memory exhaustion via abuse of protocol length headers
An attacker can cause memory exhaustion and denial of service in applications using the websocket-driver Ruby library by sending malformed protocol length headers.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54463?
CVE-2026-54463 is a medium-severity denial of service vulnerability in faye websocket-driver-ruby, 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 0.8.1, draft versions of the WebSocket protocol in websocket-driver include a length header that allows an arbitrarily large integer to be encoded as bytes with the high bit set, and a server or client can send an indefinite sequence of 0x80 or higher bytes that the peer parses into an ever-growing Ruby integer. This can make a WebSocket connection consume an unbounded amount of memory and lead to the host process running out of memory. This issue is fixed in version 0.8.1.
Weakness: CWE-770
Which versions are affected by CVE-2026-54463?
2 open source packages ship an affected version, including websocket-driver. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
websocket-driver RubyGems | All versions | 0.8.1 |
websocket-driver RubyGems | All versions | 0.8.1 |
Products include Faye Websocket-Driver.
How do I fix CVE-2026-54463?
Upgrade websocket-driver to 0.8.1 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-54463 being exploited?
There is no known exploitation of CVE-2026-54463 in the wild and no public exploit code.
Other vulnerabilities in faye websocket-driver-ruby
Sources
Also known as DEBIAN-CVE-2026-54463, GHSA-ghhp-3qvg-889p, MINI-cgmf-q496-h9m7, MINI-q4p8-m42h-hjxq, UBUNTU-CVE-2026-54463.