CVE-2026-54464 websocket-driver: Resource limit bypass via message compression
Attackers can bypass message size limits in websocket-driver when using permessage-deflate, causing resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54464?
CVE-2026-54464 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
### Impact
If this library is used in tandem with the `permessage-deflate` extension, a WebSocket server or client can be made to accept messages that are larger than the configured maximum message size. This is because this limit is checked against the message frames' length headers, which give the size of the compressed data, not the size after decompression. This can lead to applications accepting larger messages than expected and exceeding their intended resource usage.
### Patches
The issue has been patched in version 0.8.1, by checking the length of messages after they are processed by incoming extensions. All users should upgrade to this version.
### Workarounds
No known workarounds exist.
### Acknowledgements
This issue was discovered and reported by Pranjali Thakur, DepthFirst Security Research Team.
Weakness: CWE-770
Which versions are affected by CVE-2026-54464?
2 open source packages ship an affected version, including websocket-driver.
| Package | Affected | Fixed in |
|---|---|---|
websocket-driver RubyGems | All versions | 0.8.1 |
websocket-driver RubyGems | All versions | 0.8.1 |
How do I fix CVE-2026-54464?
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-2026-54464 being exploited?
There is no known exploitation of CVE-2026-54464 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-54464, GHSA-33ph-fccm-39pj, MINI-6mvc-ggj8-2gj6, MINI-jmrm-8jmw-jgjq, UBUNTU-CVE-2026-54464.