CVE-2026-62385: NLTK 3.9.4 Path Traversal via FrameNet and NKJP Readers
NLTK versions before 3.10.0 contain a path traversal vulnerability in FramenetCorpusReader and NKJPCorpusReader that allows attackers to parse XML files outside the corpus root by supplying unsafe selectors or poisoned index state. Attackers can exploit framebyname, doc, lu, and header methods with crafted parameters to read arbitrary XML files accessible to the application.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
nltk/FramenetCorpusReader and NKJPCorpusReaderto a version that resolves this vulnerability.Fixed in 3.10.0 - Upgrade
Upgrade
nltkto a version that resolves this vulnerability.Fixed in 3.10.0
Event History
Frequently Asked Questions
Which applications are exposed to this issue?
Applications using NLTK versions before 3.10.0 are exposed if they use FramenetCorpusReader or NKJPCorpusReader and allow attacker-influenced selectors or index state to reach the affected reader methods.
What does an attacker need to exploit the vulnerability?
An attacker needs to supply crafted parameters to the frame_by_name, doc, lu, or header methods, or influence poisoned index state. No authentication or user interaction is required according to the provided severity vector, but exploitation has high attack complexity.
What can an attacker access if exploitation succeeds?
The attacker can cause the application to parse XML files outside the intended corpus root. This may disclose arbitrary XML files that are accessible to the application process; the provided data does not indicate integrity or availability impact.
How can I determine whether my deployment is affected?
Check whether the application uses an NLTK release before 3.10.0 and invokes FramenetCorpusReader or NKJPCorpusReader methods such as frame_by_name, doc, lu, or header with untrusted selector values or attacker-influenced index data.
What should be done if upgrading is not immediately possible?
Do not allow untrusted input to control selectors passed to frame_by_name, doc, lu, or header, and prevent untrusted parties from modifying or supplying corpus index state. Restrict the application's access to sensitive XML files where possible.