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CVE-2026-126304 NLTK 3.10.0 before 3.10.4 Symlink Escape in YCOECorpusReader

8.7 highEPSS 0.5%Fix available

High (8.7) in nltk nltk. EPSS 0.5% estimated probability of exploitation activity in the next 30 days. Fixed in nltk 3.10.4.

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NLTK from 3.10.0 before 3.10.4 contains a symlink escape vulnerability in YCOECorpusReader that allows attackers to read files outside the corpus root by planting psd or pos directory symlinks. Attackers controlling a YCOE corpus can make parsed_sents() and tagged_words() return file content from other corpora or temporary files within the NLTK data sandbox.

Severity

CVSS 4.0

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

CVSS 3.1

7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS
0.5% estimated probability of exploitation activity in the next 30 days; 45th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-59 Improper Link Resolution Before File Access (Link Following)
OWASP Top 10
A01:2025 Broken Access Control
Published
Modified
Assigned by
VulnCheck (CNA)
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
nltkfrom 3.10.0 before 3.10.4

Fix and patched versions

  • nltk (PyPI): fixed in 3.10.4

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-qg35-44qx-7vrrPyPInltk>=3.10.0 <3.10.43.10.4

Attack patterns (CAPEC)

  • CAPEC-17 Using Malicious Files Likelihood: High · Severity: Very High
  • CAPEC-35 Leverage Executable Code in Non-Executable Files Likelihood: High · Severity: Very High
  • CAPEC-76 Manipulating Web Input to File System Calls Likelihood: High · Severity: Very High
  • CAPEC-132 Symlink Attack Likelihood: Low · Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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