Onyx is an open-source AI platform. Prior to versions 3.0.9, 3.1.6, and 3.2.6, the POST /chat/stop-chat-session/{chatsessionid} endpoint lets any authenticated user stop any other user's active chat session. The endpoint checks authentication but never verifies the session belongs to the caller. An attacker who knows a chat session UUID can kill another user's LLM generation mid-stream. This issue has been patched in versions 3.0.9, 3.1.6, and 3.2.6.
{
"cwe_ids": [
"CWE-639"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/42xxx/CVE-2026-42276.json"
}{
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "3.0.9"
},
{
"introduced": "3.1.0"
},
{
"fixed": "3.1.6"
},
{
"introduced": "3.2.0"
},
{
"fixed": "3.2.6"
}
],
"source": "CPE_RANGE",
"cpe": "cpe:2.3:a:onyx:onyx:*:*:*:*:*:*:*:*"
}