CVE-2026-54465 — websocket-driver
Fix: faye/websocket-driver-ruby@17b569fCVE-2026-54465 is a CWE-770 vulnerability in websocket-driver. A fix is available for websocket-driver — see the affected versions and patch details below.
websocket-driver: Memory exhaustion in HTTP header parser
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-54465.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
websocket-driverReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects RubyGems packages — download data is not available via public APIs for these ecosystems.
Description
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💎RubyGems | websocket-driver | all versions | 0.8.1bundle update websocket-driver --conservative |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for websocket-driver, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update websocket-driver to 0.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-54465 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-54465 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-54465. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-54465 in your dependencies?
O3 Security finds CVE-2026-54465 across RubyGems dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.