CVE-2026-62384
Description
A flaw was found in NLTK. The FramenetCorpusReader component is vulnerable to a symlink-based sandbox bypass. An attacker can exploit this by placing specially crafted symbolic links within a corpus subdirectory. These symlinks bypass path validation, allowing the attacker to read arbitrary XML files located outside the intended corpus root, leading to information disclosure.
Statement
A path traversal vulnerability exists in NLTK's FramenetCorpusReader component via symbolic links. When resolving corpus files using methods like frame_by_name(), _lu_file(), or doc(), path validation checks fail to restrict symlinks containing no path separators within subdirectories. An attacker capable of placing crafted symlinks in a corpus directory can read arbitrary XML files outside the intended corpus root. Confidentiality is impacted within the context of the running application, though standard Linux discretionary access controls and container boundaries restrict arbitrary file access beyond the process's effective permissions.
Mitigation
Restrict write permissions on NLTK corpus subdirectories to prevent unauthorized symlink creation, or sanitize input paths to prevent FramenetCorpusReader from loading untrusted corpus files containing unresolved symbolic links.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | N/A | 7.5 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | None |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality,Integrity,Access Control
Technical Impact: Read Files or Directories; Modify Files or Directories; Bypass Protection Mechanism
An attacker may be able to traverse the file system to unintended locations and read or overwrite the contents of unexpected files. If the files are used for a security mechanism than an attacker may be able to bypass the mechanism.
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