Hermes Agent before 0.16.0 contains a DNS rebinding vulnerability in WebSocket endpoints that allows remote attackers to bypass Host and Origin validation. FastAPI HTTP middleware does not execute for WebSocket upgrade requests on /api/pty, /api/ws, /api/pub, and /api/events endpoints, enabling attackers to exploit DNS rebinding and inject malicious commands or read terminal output.
{
"unresolved_ranges": [
{
"source": "AFFECTED_FIELD",
"extracted_events": [
{
"fixed": "0.16.0"
}
]
},
{
"source": "DESCRIPTION",
"extracted_events": [
{
"fixed": "0.16.0"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53869.json",
"cwe_ids": [
"CWE-306"
],
"cna_assigner": "VulnCheck"
}