PatchSiren cyber security CVE debrief
CVE-2026-54464 faye CVE debrief
CVE-2026-54464 is a vulnerability in the websocket-driver-ruby library. If this library is used 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 issue has been patched in version 0.8.1. The vulnerability allows applications to accept larger messages than expected, potentially exceeding intended resource usage. Users should be aware of this issue and upgrade to the patched version.
- Vendor
- faye
- Product
- websocket-driver-ruby
- CVSS
- MEDIUM 6.3
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-17
- Original CVE updated
- 2026-07-17
- Advisory published
- 2026-07-17
- Advisory updated
- 2026-07-17
Who should care
Users of the websocket-driver-ruby library, especially those using the `permessage-deflate` extension, should be aware of this vulnerability and upgrade to version 0.8.1. This vulnerability can lead to applications accepting larger messages than expected, potentially exceeding intended resource usage. Operators, platform administrators, and security teams should review and adjust resource usage limits for WebSocket messages.
Technical summary
The websocket-driver-ruby library does not properly check the length of messages after they are processed by incoming extensions when used with the `permessage-deflate` extension. This can lead to applications accepting larger messages than expected and exceeding their intended resource usage. The issue is addressed in version 0.8.1 by checking the length of messages after processing by incoming extensions. Defenders should review and adjust resource usage limits for WebSocket messages.
Defensive priority
Medium priority given the CVSS score of 6.3 and the availability of a patch.
Recommended defensive actions
- Upgrade to version 0.8.1 of the websocket-driver-ruby library
- Review and adjust resource usage limits for WebSocket messages
- Monitor for large messages in WebSocket applications
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
- Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
Evidence notes
Evidence is based on the CVE record and NVD detail. The CVE record was published on 2026-07-17T20:17:26.770Z and has not been modified since then. The NVD entry is currently 6.3 (Medium). Limited source detail is available; defenders should verify affected scope and vendor guidance with official advisories.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-17T20:17:26.770Z and has not been modified since then.