CVE-2026-0847
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.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.90%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.90% probability · 58th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-22
- Affected
- nltk/nltk
- Source
- security@huntr.dev
References
- https://huntr.com/bounties/fc69914f-36a9-4c18-8503-10013b39f966Exploit, Vendor Advisory
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:19712
- https://access.redhat.com/security/cve/CVE-2026-0847
- https://bugzilla.redhat.com/show_bug.cgi?id=2444608
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-0847.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.