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)
- EPSS
- 27.6%
- KEV
- Not listed
Published
July 8, 2026
Last Modified
July 10, 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(1)
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.
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 18× in last 7d / 18× 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.
- 2026-07-12 05:46 UTCEPSS rescore
- 2026-07-12 00:11 UTCEG score recompute
- 2026-07-12 00:11 UTCVendor advisory
- 2026-07-11 12:40 UTCEG score recompute
- 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 UTCEG score recompute
- 2026-07-11 01:11 UTCVendor advisory
- 2026-07-10 13:42 UTCEG score recompute
- 2026-07-10 13:42 UTCVendor advisory
- 2026-07-10 02:13 UTCEG score recompute
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 19:10 UTCEPSS rescore
- 2026-07-09 14:45 UTCEG score recompute
- 2026-07-09 03:15 UTCEG score recompute
- 2026-07-08 15:46 UTCEG score recompute
- 2026-07-08 15:45 UTCMITRE cvelistV5first tracked
Frequently asked(5)
What is CVE-2026-59725?
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Is CVE-2026-59725 actively exploited?
What is the CVSS score of CVE-2026-59725?
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Dependency Blast Radius
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