CVE-2026-59725

highCVSS 7.5covered by 1 sourcefirst seen 2026-07-08

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.

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Exploitation outlook

Low exploitation risk0.35% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 28% of all EPSS-scored CVEs.

Advisory coverage (1)

highCVE-2026-59725: Socket.IO enables bidirectional and low-latency communication for every platform. From 4.1.0 b…nvd · 2026-07-08

External references

NVD record for CVE-2026-59725

CVE.org record

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