CVE-2026-0847

HIGH

nltk <= 3.9.2 - Path Traversal in CorpusReader Classes

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2026-0847. PoCs published by HyperPS.

AI-analyzed exploit summary The repository contains a functional exploit PoC demonstrating arbitrary file read via path traversal in NLTK's CorpusReader classes. It includes both local and remote exploitation scenarios, along with detailed technical analysis and remediation guidance.

Description

A vulnerability in NLTK versions up to and including 3.9.2 allows arbitrary file read via path traversal in multiple CorpusReader classes, including WordListCorpusReader, TaggedCorpusReader, and BracketParseCorpusReader. These classes fail to properly sanitize or validate file paths, enabling attackers to traverse directories and access sensitive files on the server. This issue is particularly critical in scenarios where user-controlled file inputs are processed, such as in machine learning APIs, chatbots, or NLP pipelines. Exploitation of this vulnerability can lead to unauthorized access to sensitive files, including system files, SSH private keys, and API tokens, and may potentially escalate to remote code execution when combined with other vulnerabilities.

Exploits (1)

nomisec WORKING POC
by HyperPS · poc
https://github.com/HyperPS/CVE-2026-0847

The repository contains a functional exploit PoC demonstrating arbitrary file read via path traversal in NLTK's CorpusReader classes. It includes both local and remote exploitation scenarios, along with detailed technical analysis and remediation guidance.

Classification
Working Poc 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: NLTK <= 3.9.2
No auth needed
Prerequisites: User-controlled input to NLTK CorpusReader file paths
devstral-2 · analyzed Apr 09, 2026 Full analysis →

References (1)

Core 1
Core References

Scores

CVSS v3 7.5
EPSS 0.0008
EPSS Percentile 23.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CISA SSVC

Vulnrichment
Exploitation poc
Automatable yes
Technical Impact partial

Details

CWE
CWE-22
Status published
Products (2)
nltk/nltk < 3.9.2
pypi/nltk 0 - 3.9.2PyPI
Published Mar 04, 2026
Tracked Since Mar 05, 2026