websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite sequence of bytes with values 0x80 or above, a client can make the server parse these bytes into an ever-growing integer in lib/websocket/driver/draft75.js; because JavaScript numbers are 64-bit floating point values, this number will eventually lose precision and lead to the subsequent payload being parsed incorrectly. This issue is fixed in version 0.7.5.
CVE-2026-54466
CRITICALPre-NVD 9.29.2—Trending — 3 sources updated this week
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 9.2 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 64% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
9.2
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.2Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.2
- EG Score
- 9.2(medium)
- EPSS
- 36.3%
- KEV
- Not listed
Published
July 15, 2026
Last Modified
July 20, 2026
Advisory Details (2)
Auto-updated Jul 17, 2026Patch available. Sources: github_commit, github.
github Patch Available
Message corruption via abuse of protocol length headers · Advisory · faye/websocket-driver-node · GitHub
Affected: version 0.7.5 by rejecting the message if the
https://github.com/faye/websocket-driver-node/security/advisories/GHSA-xv26-6w52-cph6github_commit
commit 5b197ca874da (faye/websocket-driver-node)
Fix landed in faye/websocket-driver-node commit 5b197ca874da — awaiting tagged release
https://github.com/faye/websocket-driver-node/commit/5b197ca874dab58e96cacad8a3c256797d804680Vendor Advisories for CVE-2026-54466(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| websocket-driver | — | 0.7.5 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 10× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 02:36 UTCEG score recompute
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-17 21:00 UTCEG score recompute▲ 9.20
- 2026-07-17 20:59 UTCMITRE cvelistV5CVSS v3 → 9.2 · CVSS v4 → 9.2
- 2026-07-15 22:19 UTCEG score recompute
Frequently asked(5)
What is CVE-2026-54466?
CVE-2026-54466 is a critical vulnerability published on July 15, 2026. websocket-driver is a WebSocket protocol handler with pluggable I/O. Prior to 0.7.5, the frame format in draft versions of the WebSocket protocol includes a length header that allows an arbitrarily large integer to be encoded as a sequence of bytes with the high bit set. By sending an indefinite…
When was CVE-2026-54466 disclosed?
CVE-2026-54466 was first published in the National Vulnerability Database on July 15, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-54466 actively exploited?
CVE-2026-54466 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 36.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-54466?
CVE-2026-54466 has a CVSS v3 base score of 9.2 (NVD).
How do I remediate CVE-2026-54466?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-54466, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54466
Is Your Infrastructure Affected by CVE-2026-54466?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.