CVE-2026-59724

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

Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 before 6.6.7, Engine.IO servers with WebTransport enabled can resolve a crafted session ID such as proto through an inherited property of the clients object during WebTransport upgrade handling, causing a TypeError and denial of service. This issue is fixed in version 6.6.7.

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Exploitation outlook

Low exploitation risk0.34% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 26% of all EPSS-scored CVEs.

Advisory coverage (1)

highCVE-2026-59724: Socket.IO enables bidirectional and low-latency communication for every platform. From 6.5.0 b…nvd · 2026-07-08

External references

NVD record for CVE-2026-59724

CVE.org record

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