Skip to content
Heist/ feed
UnratedFix available

DEBIAN-CVE-2026-33248

Type: advisorySource: OSV1 source record

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, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass. This does require a valid certificate from a CA already trusted for client certificates, and `DN` naming patterns which the NATS maintainers consider highly unlikely. So this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their `DN` construction patterns might conceivably be impacted. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, developers should review their CA issuing practices.

Announced Group revision 1
Original source ↗

DEBIAN-CVE-2026-33248

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: osv:DEBIAN-CVE-2026-33248

nats-server

Source reference: /affected/0/package/name

Affected versions
2.10.1-1

Source reference: /affected/0/versions

2.10.16-1

Source reference: /affected/0/versions

2.10.18-1

Source reference: /affected/0/versions

2.10.24-1

Source reference: /affected/0/versions

2.10.27-1

Source reference: /affected/0/versions

2.10.3-1

Source reference: /affected/0/versions

2.10.4-1

Source reference: /affected/0/versions

2.10.7-1

Source reference: /affected/0/versions

2.12.4-1

Source reference: /affected/0/versions

2.12.6-1

Source reference: /affected/0/versions

2.14.1-1

Source reference: /affected/0/versions

2.14.3-1

Source reference: /affected/0/versions

2.14.6-1

Source reference: /affected/0/versions

2.9.10-1

Source reference: /affected/0/versions

2.9.19-1

Source reference: /affected/0/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

nats-server

Source reference: /affected/1/package/name

Affected versions
2.10.27-1

Source reference: /affected/1/versions

2.12.4-1

Source reference: /affected/1/versions

2.12.6-1

Source reference: /affected/1/versions

2.14.1-1

Source reference: /affected/1/versions

2.14.3-1

Source reference: /affected/1/versions

2.14.6-1

Source reference: /affected/1/versions

Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

nats-server

Source reference: /affected/2/package/name

Affected versions
2.10.27-1

Source reference: /affected/2/versions

2.12.4-1

Source reference: /affected/2/versions

Fixed versions
2.12.6-1

Source reference: /affected/2/ranges

Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "nats-server",
      "purl": "pkg:deb/debian/nats-server?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "2.10.1-1",
      "2.10.16-1",
      "2.10.18-1",
      "2.10.24-1",
      "2.10.27-1",
      "2.10.3-1",
      "2.10.4-1",
      "2.10.7-1",
      "2.12.4-1",
      "2.12.6-1",
      "2.14.1-1",
      "2.14.3-1",
      "2.14.6-1",
      "2.9.10-1",
      "2.9.19-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33248.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "nats-server",
      "purl": "pkg:deb/debian/nats-server?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "2.10.27-1",
      "2.12.4-1",
      "2.12.6-1",
      "2.14.1-1",
      "2.14.3-1",
      "2.14.6-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33248.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "2.12.6-1"
          }
        ]
      }
    ],
    "package": {
      "name": "nats-server",
      "purl": "pkg:deb/debian/nats-server?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "2.10.27-1",
      "2.12.4-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33248.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#55943 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement