GHSA-3m7f-6hxv-6796

Suggest an improvement
Source
https://github.com/advisories/GHSA-3m7f-6hxv-6796
Import Source
https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-3m7f-6hxv-6796/GHSA-3m7f-6hxv-6796.json
JSON Data
https://api.osv.dev/v1/vulns/GHSA-3m7f-6hxv-6796
Withdrawn
2026-09-02T14:49:56Z
Published
2026-08-27T18:32:30Z
Modified
2026-09-02T15:00:09Z
Severity
  • 3.7 (Low) CVSS_V3 - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L CVSS Calculator
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/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 CVSS Calculator
Summary
Duplicate Advisory: Pl196xCorpusReader has quadratic ReDoS on malformed TEI blocks
Details

Duplicate Advisory

This advisory has been withdrawn because it is a duplicate of GHSA-8mpw-7fpc-4gqj. This link is maintained to preserve external references.

Original Description

NLTK before 3.10.3 contains a regular expression denial of service vulnerability in Pl196xCorpusReader that allows attackers to cause quadratic CPU consumption by supplying malformed TEI blocks with many unmatched opening tags. Attackers can exploit lazy regex patterns in the read_block method through public APIs like words() and tagged_words() to force repeated rescans and achieve near-quadratic runtime growth.

Database specific 
{
    "cwe_ids":  [
        "CWE-400"
    ],
    "github_reviewed":  true,
    "github_reviewed_at":  "2026-09-02T14:49:56Z",
    "nvd_published_at":  "2026-08-27T17:21:03Z",
    "severity":  "MODERATE"
}
References

Affected packages

PyPI / nltk

Package

Name
nltk
View open source insights on deps.dev
Purl
pkg:pypi/nltk

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0 Unknown introduced version / All previous versions are affected
Last Affected
3.10.2

Affected versions

2.*
2.0.1rc2-git
2.0b4
2.0b5
2.0b6
2.0b7
2.0b8
2.0b9
2.0.1rc1
2.0.1rc3
2.0.1rc4
2.0.1
2.0.2
2.0.3
2.0.4
2.0.5
0.*
0.8
0.9
0.9.3
0.9.4
0.9.5
0.9.6
0.9.7
0.9.8
0.9.9
3.*
3.0.0b1
3.0.0b2
3.0.0
3.0.1
3.0.2
3.0.3
3.0.4
3.0.5
3.1
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.3
3.4
3.4.1
3.4.2
3.4.3
3.4.4
3.4.5
3.5b1
3.5
3.6
3.6.1
3.6.2
3.6.3
3.6.4
3.6.5
3.6.6
3.6.7
3.7
3.8
3.8.1
3.9b1
3.9
3.9.1
3.9.2
3.9.3
3.9.4
3.10.0
3.10.1
3.10.2

Database specific

source 
"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-3m7f-6hxv-6796/GHSA-3m7f-6hxv-6796.json"