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DEBIAN-CVE-2026-80205

Type: advisorySource: OSV1 source record

NLTK versions before 3.10.0 contain a regular expression denial of service vulnerability in Text.findall() and TokenSearcher.findall() methods that accept user-supplied regular expressions without validation or timeout. Attackers can supply crafted regex patterns that cause catastrophic backtracking, resulting in indefinite CPU saturation and denial of service to all users of the Python process.

Announced Group revision 1
Original source ↗

DEBIAN-CVE-2026-80205

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-2026-80205

nltk

Source reference: /affected/0/package/name

Affected versions
3.10.0-1

Source reference: /affected/0/versions

3.10.1-1

Source reference: /affected/0/versions

3.10.3-1

Source reference: /affected/0/versions

3.8-1

Source reference: /affected/0/versions

3.8.1-1

Source reference: /affected/0/versions

3.9.1-1

Source reference: /affected/0/versions

3.9.1-2

Source reference: /affected/0/versions

3.9.2-1

Source reference: /affected/0/versions

3.9.3-1

Source reference: /affected/0/versions

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

nltk

Source reference: /affected/1/package/name

Affected versions
3.10.0-1

Source reference: /affected/1/versions

3.10.1-1

Source reference: /affected/1/versions

3.10.3-1

Source reference: /affected/1/versions

3.9.1-2

Source reference: /affected/1/versions

3.9.2-1

Source reference: /affected/1/versions

3.9.3-1

Source reference: /affected/1/versions

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

nltk

Source reference: /affected/2/package/name

Affected versions
3.9.1-2

Source reference: /affected/2/versions

3.9.2-1

Source reference: /affected/2/versions

3.9.3-1

Source reference: /affected/2/versions

Fixed versions
3.10.0-1

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": "nltk",
      "purl": "pkg:deb/debian/nltk?arch=source&distro=bookworm",
      "ecosystem": "Debian:12"
    },
    "versions": [
      "3.10.0-1",
      "3.10.1-1",
      "3.10.3-1",
      "3.8-1",
      "3.8.1-1",
      "3.9.1-1",
      "3.9.1-2",
      "3.9.2-1",
      "3.9.3-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80205.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          }
        ]
      }
    ],
    "package": {
      "name": "nltk",
      "purl": "pkg:deb/debian/nltk?arch=source&distro=trixie",
      "ecosystem": "Debian:13"
    },
    "versions": [
      "3.10.0-1",
      "3.10.1-1",
      "3.10.3-1",
      "3.9.1-2",
      "3.9.2-1",
      "3.9.3-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80205.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  },
  {
    "ranges": [
      {
        "type": "ECOSYSTEM",
        "events": [
          {
            "introduced": "0"
          },
          {
            "fixed": "3.10.0-1"
          }
        ]
      }
    ],
    "package": {
      "name": "nltk",
      "purl": "pkg:deb/debian/nltk?arch=source&distro=forky",
      "ecosystem": "Debian:14"
    },
    "versions": [
      "3.9.1-2",
      "3.9.2-1",
      "3.9.3-1"
    ],
    "database_specific": {
      "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-80205.json"
    },
    "ecosystem_specific": {
      "urgency": "not yet assigned"
    }
  }
]

Publisher severity

No explicit severity was provided.

Event
#58207 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement