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DEBIAN-CVE-2026-33603

Type: advisorySource: OSV1 source record

Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. Install fixed version. No publicly available exploits are known.

Announced Group revision 1
Original source ↗

DEBIAN-CVE-2026-33603

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-2026-33603

dovecot

Source reference: /affected/0/package/name

Affected versions
1:2.3.19.1+dfsg1-2.1

Source reference: /affected/0/versions

1:2.3.19.1+dfsg1-2.1+deb12u1

Source reference: /affected/0/versions

1:2.3.19.1+dfsg1-2.1+deb12u2

Source reference: /affected/0/versions

1:2.3.19.1+dfsg1-2.1+deb12u3

Source reference: /affected/0/versions

1:2.3.19.1+dfsg1-2.1+deb12u4

Source reference: /affected/0/versions

1:2.3.19.1+dfsg1-2.1+deb12u5

Source reference: /affected/0/versions

Fixed versions
1:2.3.19.1+dfsg1-2.1+deb12u6

Source reference: /affected/0/ranges

Prerequisites
Not stated in this record

dovecot

Source reference: /affected/1/package/name

Affected versions
1:2.4.1+dfsg1-6

Source reference: /affected/1/versions

1:2.4.1+dfsg1-6+deb13u1

Source reference: /affected/1/versions

1:2.4.1+dfsg1-6+deb13u2

Source reference: /affected/1/versions

1:2.4.1+dfsg1-6+deb13u3

Source reference: /affected/1/versions

1:2.4.1+dfsg1-6+deb13u4

Source reference: /affected/1/versions

1:2.4.1+dfsg1-6+deb13u5

Source reference: /affected/1/versions

Fixed versions
1:2.4.1+dfsg1-6+deb13u6

Source reference: /affected/1/ranges

Prerequisites
Not stated in this record

dovecot

Source reference: /affected/2/package/name

Affected versions
1:2.4.1+dfsg1-6

Source reference: /affected/2/versions

1:2.4.1+dfsg1-7

Source reference: /affected/2/versions

1:2.4.1+dfsg1-8

Source reference: /affected/2/versions

1:2.4.1+dfsg1-9

Source reference: /affected/2/versions

1:2.4.2+dfsg1-1

Source reference: /affected/2/versions

1:2.4.2+dfsg1-2

Source reference: /affected/2/versions

1:2.4.2+dfsg1-3

Source reference: /affected/2/versions

1:2.4.2+dfsg1-4

Source reference: /affected/2/versions

1:2.4.3+dfsg1-1

Source reference: /affected/2/versions

1:2.4.3+dfsg1-2

Source reference: /affected/2/versions

Fixed versions
1:2.4.4+dfsg1-1

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": "1:2.3.19.1+dfsg1-2.1+deb12u6"
          }
        ]
      }
    ],
    "package": {
      "name": "dovecot",
      "purl": "pkg:deb/debian/dovecot?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "1:2.3.19.1+dfsg1-2.1",
      "1:2.3.19.1+dfsg1-2.1+deb12u1",
      "1:2.3.19.1+dfsg1-2.1+deb12u2",
      "1:2.3.19.1+dfsg1-2.1+deb12u3",
      "1:2.3.19.1+dfsg1-2.1+deb12u4",
      "1:2.3.19.1+dfsg1-2.1+deb12u5"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33603.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1:2.4.1+dfsg1-6+deb13u6"
          }
        ]
      }
    ],
    "package": {
      "name": "dovecot",
      "purl": "pkg:deb/debian/dovecot?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "1:2.4.1+dfsg1-6",
      "1:2.4.1+dfsg1-6+deb13u1",
      "1:2.4.1+dfsg1-6+deb13u2",
      "1:2.4.1+dfsg1-6+deb13u3",
      "1:2.4.1+dfsg1-6+deb13u4",
      "1:2.4.1+dfsg1-6+deb13u5"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33603.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "1:2.4.4+dfsg1-1"
          }
        ]
      }
    ],
    "package": {
      "name": "dovecot",
      "purl": "pkg:deb/debian/dovecot?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "1:2.4.1+dfsg1-6",
      "1:2.4.1+dfsg1-7",
      "1:2.4.1+dfsg1-8",
      "1:2.4.1+dfsg1-9",
      "1:2.4.2+dfsg1-1",
      "1:2.4.2+dfsg1-2",
      "1:2.4.2+dfsg1-3",
      "1:2.4.2+dfsg1-4",
      "1:2.4.3+dfsg1-1",
      "1:2.4.3+dfsg1-2"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-33603.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#57529 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement

Revision history

  1. DEBIAN-CVE-2026-33603 · Revision 1Source updated