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DEBIAN-CVE-2026-33721

Type: advisorySource: OSV1 source record

MapServer is a system for developing web-based GIS applications. Starting in version 4.2 and prior to version 8.6.1, a heap-buffer-overflow write in MapServer’s SLD (Styled Layer Descriptor) parser lets a remote, unauthenticated attacker crash the MapServer process by sending a crafted SLD with more than 100 Threshold elements inside a ColorMap/Categorize structure (commonly reachable via WMS GetMap with SLD_BODY). Version 8.6.1 patches the issue.

Announced Group revision 1
Original source ↗

DEBIAN-CVE-2026-33721

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-2026-33721

mapserver

Source reference: /affected/0/package/name

Affected versions
8.0.0-3

Source reference: /affected/0/versions

Fixed versions
8.0.0-3+deb12u1

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

mapserver

Source reference: /affected/1/package/name

Affected versions
8.4.0-4

Source reference: /affected/1/versions

8.4.0-4+deb13u1

Source reference: /affected/1/versions

Fixed versions
8.4.0-4+deb13u2

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

mapserver

Source reference: /affected/2/package/name

Affected versions
8.4.0-4

Source reference: /affected/2/versions

8.4.1-1

Source reference: /affected/2/versions

8.4.1-1~bpo13+1

Source reference: /affected/2/versions

8.4.1-2

Source reference: /affected/2/versions

8.6.0-1

Source reference: /affected/2/versions

8.6.0-1~bpo13+1

Source reference: /affected/2/versions

8.6.0~beta1-1~exp1

Source reference: /affected/2/versions

8.6.0~beta2-1~exp1

Source reference: /affected/2/versions

8.6.0~rc1-1~exp1

Source reference: /affected/2/versions

8.6.1-1~bpo13+1

Source reference: /affected/2/versions

Fixed versions
8.6.1-1

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"
          },
          {
            "fixed": "8.0.0-3+deb12u1"
          }
        ]
      }
    ],
    "package": {
      "name": "mapserver",
      "purl": "pkg:deb/debian/mapserver?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "8.0.0-3"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33721.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "8.4.0-4+deb13u2"
          }
        ]
      }
    ],
    "package": {
      "name": "mapserver",
      "purl": "pkg:deb/debian/mapserver?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "8.4.0-4",
      "8.4.0-4+deb13u1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33721.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "8.6.1-1"
          }
        ]
      }
    ],
    "package": {
      "name": "mapserver",
      "purl": "pkg:deb/debian/mapserver?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "8.4.0-4",
      "8.4.1-1",
      "8.4.1-1~bpo13+1",
      "8.4.1-2",
      "8.6.0-1",
      "8.6.0-1~bpo13+1",
      "8.6.0~beta1-1~exp1",
      "8.6.0~beta2-1~exp1",
      "8.6.0~rc1-1~exp1",
      "8.6.1-1~bpo13+1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33721.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#57585 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. DEBIAN-CVE-2026-33721 · Revision 1Source updated