NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.
{
"cwe_ids": [
"CWE-20"
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33218.json",
"cna_assigner": "GitHub_M"
}{
"extracted_events": [
{
"introduced": "2.12.0-RC.1"
},
{
"fixed": "2.12.6"
},
{
"introduced": "< < 2.11.15"
},
{
"last_affected": "< < 2.11.15"
}
],
"source": "AFFECTED_FIELD"
}