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.
{
"cna_assigner": "GitHub_M",
"cwe_ids": [
"CWE-404"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59725.json"
}{
"extracted_events": [
{
"cpe": "cpe:2.3:a:socket:engine.io:*:*:*:*:*:node.js:*:*",
"range": [
{
"introduced": "4.1.0"
},
{
"fixed": "6.6.7"
}
],
"source": "CPE_RANGE"
},
{
"range": [
{
"fixed": "fc11285e14964c2132d122164bf130c355f60671"
}
],
"source": "REFERENCES_COMMIT"
},
{
"original_tag": "engine.io@6.6.7",
"range": [
{
"fixed": "439a8f669c6788b512dd76011c4476830d67515b"
}
],
"source": "REFERENCES_TAG"
}
]
}