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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
2026-07-21
Advisory published
2026-07-17
Advisory updated
2026-07-21

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.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-54464 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-54464

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-54464 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-54464

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.