Vulnerability-Lookup

GHSA-2RRW-HPQM-36PV

Vulnerability from github – Published: 2026-08-26 18:31 – Updated: 2026-09-08 20:27

Withdrawn 2026-09-08

Summary

Duplicate Advisory: ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions

Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-rrv8-h7p8-rx55. This link is maintained to preserve external references.

Original Description

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.

Severity

7.5 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

8.7 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Show details on source website

JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "nltk"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "3.9.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-1333"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-08T20:27:59Z",
    "nvd_published_at": "2026-08-26T11:16:39Z",
    "severity": "HIGH"
  },
  "details": "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of\u00a0GHSA-rrv8-h7p8-rx55. This link is maintained to preserve external references.\n\n## Original Description\nNLTK 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.",
  "id": "GHSA-2rrw-hpqm-36pv",
  "modified": "2026-09-08T20:27:59Z",
  "published": "2026-08-26T18:31:54Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nltk/nltk/security/advisories/GHSA-rrv8-h7p8-rx55"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80205"
    },
    {
      "type": "WEB",
      "url": "https://www.vulncheck.com/advisories/nltk-before-3.10.0-redos-via-text-findall-unvalidated-regex"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/09/01/3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Duplicate Advisory:  ReDoS in nltk.text.Text.findall() via unvalidated user-supplied regular expressions",
  "withdrawn": "2026-09-08T20:27:59Z"
}

CVE-2026-80205 (GCVE-0-2026-80205)

Vulnerability from cvelistv5 – Published: 2026-08-26 10:28 – Updated: 2026-09-01 22:06

Title

NLTK before 3.10.0 ReDoS via Text.findall() unvalidated regex

Summary

Severity

8.7 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

7.5 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 15:58 UTC

CWE

CWE-1333 - Inefficient Regular Expression Complexity

Assigner

VulnCheck mitre root

References

3 references

URL	Tags
https://github.com/nltk/nltk/security/advisories/…	vendor-advisory
https://www.vulncheck.com/advisories/nltk-before-…	third-party-advisory
http://www.openwall.com/lists/oss-security/2026/09/01/3

Impacted products

1 product

Vendor	Product	Version
nltk	nltk	Affected: 0 , < 3.10.0 (semver) Unaffected: 3.10.0 (semver) cpe:2.3:a:nltk:nltk::::::::

Date Public

2026-08-12 00:00

Credits

infycore ekaf agent-kira

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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