CVE-2026-54465: websocket-driver: Memory exhaustion in HTTP header parser
Impact
If this library is used to implement a WebSocket server on top of a TCP server (rather than an HTTP server or framework) using the WebSocket::Driver.server() method, or, if it is used to complement a WebSocket client, then a peer can make a single connection consume an unbounded amount of memory by sending an HTTP request or response with a never-ending list of headers. This can lead to the receiving process running out of memory.
Patches
The issue has been patched in version 0.8.1, by limiting the total size of HTTP request/response lines and headers accepted by the parser to 32 kB. 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.
Other sources
websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.8.1, when websocket-driver is used to implement a WebSocket server on top of a TCP server using WebSocket::Driver.server() or to complement a WebSocket client, a peer can make a single connection consume an unbounded amount of memory by sending an HTTP request or response with a never-ending list of headers. This can lead to the receiving process running out of memory. This issue is fixed in version 0.8.1.
— MITRE
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
rubygems/websocket-driverto a version that resolves this vulnerability.Fixed in 0.8.1 - Upgrade
Upgrade
websocket-driverto a version that resolves this vulnerability.Fixed in 0.8.1
Event History
Frequently Asked Questions
What is the severity of CVE-2026-54465?
The severity of CVE-2026-54465 is medium with a CVSS score of 6.3.
What software is affected by CVE-2026-54465?
The CVE-2026-54465 vulnerability affects the websocket-driver library used in Ruby applications.
How does CVE-2026-54465 impact users?
CVE-2026-54465 allows a peer to cause a WebSocket server to exhaust memory through unbounded HTTP header parsing.
How do I fix CVE-2026-54465?
To fix CVE-2026-54465, upgrade the websocket-driver library to version 0.8.1 or later.
When was CVE-2026-54465 published?
CVE-2026-54465 was published on July 15, 2026.