GHSA-8h9m-22mv-qv5r: Duplicate Advisory Symlink Escape Vulnerability

HIGH
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CVSS 6.2
CWE-59
Published
Advisory Summary

GHSA-8h9m-22mv-qv5r is a HIGH (CVSS 6.2) symlink escape vulnerability (CWE-59: Improper Link Resolution Before File Access ('Link Following')) affecting Duplicate Advisory libraries in the PyPI ecosystem. The issue involves symlink escape in corpusreader allows arbitrary local file read outside the corpus root. Remediation is available in the latest vendor maintenance releases.

GHSA-8h9m-22mv-qv5r at a Glance

CVE Identifier N/A
GHSA Identifier GHSA-8h9m-22mv-qv5r
Severity HIGH
CVSS v3.1 Base Score 6.2
CWE Classification CWE-59: Improper Link Resolution Before File Access ('Link Following')
Affected Product Duplicate Advisory
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 6.2

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Local (AV:L)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix GHSA-8h9m-22mv-qv5r

To remediate this vulnerability, upgrade all affected Duplicate Advisory dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

nltk fixed: Latest secure release 
pip install nltk>=Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show nltk

How to Check if You Are Affected

To determine whether your Python environment is affected by GHSA-8h9m-22mv-qv5r, inspect your installed packages using pip:

pip show nltk

Analyze the terminal output to locate any version of Duplicate Advisory in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The pip show nltk command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following'), where the product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource. In Duplicate Advisory, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## Duplicate Advisory This advisory has been withdrawn because it is a duplicate of GHSA-r6gq-whwq-mvg9. This link is maintained to preserve external references. ## Original Description NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.

GHSA-8h9m-22mv-qv5r Affected Duplicate Advisory Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
nltk
pypi/nltk
PyPI
≤ 3.9.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9
NVD — GHSA-8h9m-22mv-qv5r NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-70626
www.vulncheck.com/advisories/nltk-bef... WEB
https://www.vulncheck.com/advisories/nltk-before-symlink-escape-via-corpusreader

Frequently Asked Questions

What is GHSA-8h9m-22mv-qv5r?
GHSA-8h9m-22mv-qv5r is a security vulnerability in Duplicate Advisory involving Symlink escape in CorpusReader allows arbitrary local file read outside the corpus root under CWE-59: Improper Link Resolution Before File Access ('Link Following').
Which Duplicate Advisory versions are affected?
Affected versions include releases prior to current release patches across affected packages: nltk.
What version fixes GHSA-8h9m-22mv-qv5r?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is nltk affected?
Yes, nltk is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of GHSA-8h9m-22mv-qv5r?
GHSA-8h9m-22mv-qv5r has a CVSS v3.1 base score of 6.2 (HIGH) with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with GHSA-8h9m-22mv-qv5r?
GHSA-8h9m-22mv-qv5r is classified under CWE-59: Improper Link Resolution Before File Access ('Link Following') (The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.).
How can I check PyPI dependencies for GHSA-8h9m-22mv-qv5r?
Run the dependency tree command: 'pip show nltk'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8h9m-22mv-qv5r",
  "modified" : "2026-09-02T14:48:09Z",
  "published" : "2026-08-22T15:31:04Z",
  "withdrawn" : "2026-09-02T14:48:09Z",
  "aliases" : [ ],
  "summary" : "Duplicate Advisory: Symlink escape in CorpusReader allows arbitrary local file read outside the corpus root",
  "details" : "## Duplicate Advisory\n\nThis advisory has been withdrawn because it is a duplicate of GHSA-r6gq-whwq-mvg9. This link is maintained to preserve external references.\n\n## Original Description\nNLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "nltk"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "3.9.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-70626"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/nltk-before-symlink-escape-via-corpusreader"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-59" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-02T14:48:09Z",
    "nvd_published_at" : "2026-08-22T15:16:21Z"
  }
}