Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 before 6.6.7, Engine.IO protocol v4 polling transport does not properly close the HTTP response for invalid binary POST requests with Content-Type: application/octet-stream, allowing an unauthenticated attacker to exhaust server-side connections and sockets. This issue is fixed in version 6.6.7.
CVE-2026-59725
This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 72% 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).
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5(medium)
- EG Risk
- 49(Track)EG Risk 49/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 0%
- EPSS %ILE
- 28%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 13, 2026
Advisory Details (3)
Auto-updated Jul 8, 2026Engine.IO Polling Transport Connection Exhaustion · Advisory · socketio/socket.io · GitHub
https://github.com/socketio/socket.io/security/advisories/GHSA-r635-g3xr-vw7x[email protected]
Patch available: socketio/socket.io [email protected]
https://github.com/socketio/socket.io/releases/tag/[email protected]commit fc11285e1496 (socketio/socket.io)
Patch available: socketio/socket.io [email protected] (contains commit fc11285e1496)
https://github.com/socketio/socket.io/commit/fc11285e14964c2132d122164bf130c355f60671Vendor Advisories for CVE-2026-59725(2)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | dotnet8-0-main-8.0.128-1.1.hum1 | 2026-07-10 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| engine.io | — | 6.6.7 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 20× in last 7d / 53× 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.
- 2026-07-27 14:14 UTCEPSS rescore
- 2026-07-27 11:25 UTCVendor advisory
- 2026-07-26 23:57 UTCEG score recompute
- 2026-07-26 23:57 UTCVendor advisory
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-26 14:54 UTCEPSS rescore
- 2026-07-26 12:27 UTCEG score recompute
- 2026-07-26 12:27 UTCVendor advisory
- 2026-07-25 14:18 UTCEPSS rescore
- 2026-07-25 14:18 UTCEPSS rescore
- 2026-07-24 14:18 UTCEPSS rescore
- 2026-07-24 14:18 UTCEPSS rescore
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 14:18 UTCEPSS rescore
- 2026-07-23 03:21 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 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 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-17 06:32 UTCVendor advisory
- 2026-07-16 19:02 UTCVendor advisory
Show 28 moreShow fewer
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-16 07:32 UTCVendor advisory
- 2026-07-15 20:04 UTCVendor advisory
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 16:57 UTCEPSS rescore
- 2026-07-15 08:34 UTCVendor advisory
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-15 02:00 UTCEPSS rescore
- 2026-07-14 21:05 UTCVendor advisory
- 2026-07-14 09:36 UTCVendor advisory
- 2026-07-13 22:31 UTCEPSS rescore
- 2026-07-13 22:08 UTCVendor advisory
- 2026-07-13 10:40 UTCVendor advisory
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-13 06:13 UTCEPSS rescore
- 2026-07-12 23:09 UTCVendor advisory
- 2026-07-12 11:41 UTCVendor advisory
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-12 00:11 UTCVendor advisory
- 2026-07-11 12:40 UTCVendor advisory
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 08:27 UTCEPSS rescore
- 2026-07-11 01:11 UTCVendor advisory
- 2026-07-10 13:42 UTCVendor advisory
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-08 15:46 UTCEG score recompute
- 2026-07-08 15:45 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-59725?
When was CVE-2026-59725 disclosed?
Is CVE-2026-59725 actively exploited?
What is the CVSS score of CVE-2026-59725?
How do I remediate CVE-2026-59725?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-59725
Is Your Infrastructure Affected by CVE-2026-59725?
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