Medium
nats-server — security advisory
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
- Products
- nats-server
- Affected versions
- 2.10.24-1, 2.10.27-1, 2.10.27-1build1, 2.10.27-1ubuntu0.26.04.1~esm1, 2.10.3-1, 2.10.4-1, 2.10.7-1, 2.10.7-1ubuntu0.1, 2.10.7-1ubuntu0.2, 2.10.7-1ubuntu0.3, 2.14.1-1, 2.14.3-1, 2.9.19-1build1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-33249
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 03:00 UTC · Revision 1
Source evidence
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
osv:UBUNTU-CVE-2026-33249
nats-server
Fixed versions: Not specified
nats-server
Fixed versions: Not specified
nats-server
Fixed versions: Not specified
nats-server
Fixed versions: Not specified
Complete source record
{
"id": "d2f3858fcd68e5e78c2916e7e8e839beb39cb5510495508bb60730452f6811e8",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-33249",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-33249",
"summary": "NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.",
"evidence": "osv:UBUNTU-CVE-2026-33249",
"products": [
{
"name": {
"value": "nats-server",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.9.19-1build1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.7-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.7-1ubuntu0.1",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.7-1ubuntu0.2",
"evidence": "/affected/0/versions"
},
{
"value": "2.10.7-1ubuntu0.3",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "nats-server",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.24-1",
"evidence": "/affected/1/versions"
},
{
"value": "2.10.27-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "nats-server",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.27-1build1",
"evidence": "/affected/2/versions"
},
{
"value": "2.14.1-1",
"evidence": "/affected/2/versions"
},
{
"value": "2.14.3-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
"value": "nats-server",
"evidence": "/affected/3/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.10.27-1",
"evidence": "/affected/3/versions"
},
{
"value": "2.10.27-1build1",
"evidence": "/affected/3/versions"
},
{
"value": "2.10.27-1ubuntu0.26.04.1~esm1",
"evidence": "/affected/3/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-33249",
"aliases": [
"UBUNTU-CVE-2026-33249"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=noble",
"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"2.9.19-1build1",
"2.10.3-1",
"2.10.4-1",
"2.10.7-1",
"2.10.7-1ubuntu0.1",
"2.10.7-1ubuntu0.2",
"2.10.7-1ubuntu0.3"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33249.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-nats-io-nats-server-dev",
"binary_version": "2.10.7-1ubuntu0.3"
},
{
"binary_name": "nats-server",
"binary_version": "2.10.7-1ubuntu0.3"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=questing",
"ecosystem": "Ubuntu:25.10"
},
"versions": [
"2.10.24-1",
"2.10.27-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33249.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-nats-io-nats-server-dev",
"binary_version": "2.10.27-1"
},
{
"binary_name": "nats-server",
"binary_version": "2.10.27-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=stonking",
"ecosystem": "Ubuntu:26.10"
},
"versions": [
"2.10.27-1build1",
"2.14.1-1",
"2.14.3-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33249.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-nats-io-nats-server-dev",
"binary_version": "2.14.3-1"
},
{
"binary_name": "nats-server",
"binary_version": "2.14.3-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "nats-server",
"purl": "pkg:deb/ubuntu/nats-server?arch=source&distro=esm-apps%2Fresolute",
"ecosystem": "Ubuntu:Pro:26.04:LTS"
},
"versions": [
"2.10.27-1",
"2.10.27-1build1",
"2.10.27-1ubuntu0.26.04.1~esm1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-33249.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "golang-github-nats-io-nats-server-dev",
"binary_version": "2.10.27-1ubuntu0.26.04.1~esm1"
},
{
"binary_name": "nats-server",
"binary_version": "2.10.27-1ubuntu0.26.04.1~esm1"
}
]
}
}
],
"modified": "2026-10-17T13:00:00.903761029Z",
"provider": "osv",
"upstream": [
"CVE-2026-33249"
],
"references": [
"https://ubuntu.com/security/CVE-2026-33249",
"https://www.cve.org/CVERecord?id=CVE-2026-33249",
"https://advisories.nats.io/CVE/secnote-2026-15.txt",
"https://github.com/nats-io/nats-server/security/advisories/GHSA-8m2x-3m6q-6w8j"
]
},
"related_cves": [
{
"value": "CVE-2026-33249",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 360123,
"published_at": "2026-03-25T21:16:00+00:00"
}