EUVD-2026-65526
GHSA-w5q8-6jpp-4246
Severity by source
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
PR:L reflects required write access to the corpus directory to stage symlinks; AC:H reflects the symlink pre-staging prerequisite; C:H and I:N/A:N match file-disclosure-only impact with no write or availability consequence.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Lifecycle Timeline
3DescriptionCVE.org
NLTK versions before 3.10.3 contain a path traversal vulnerability in corpus readers that reopen root-derived paths using built-in open() instead of nltk.pathsec.open(), allowing symlinks to escape trusted roots. Attackers who stage symlinked corpus files under a trusted data root can disclose outside-root content through normal corpus reader methods like channels(), domains(), and synonyms().
AnalysisAI
Path traversal via symlink bypass in NLTK corpus readers before 3.10.3 permits disclosure of arbitrary files outside the trusted corpus data root through standard API calls. Affected corpus reader methods - channels(), domains(), and synonyms() - reopen root-derived paths with Python's built-in open() rather than the secure nltk.pathsec.open(), which enforces symlink restrictions. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires the attacker to have write access to at least one NLTK trusted corpus data root directory in order to stage a crafted symbolic link - this is the decisive prerequisite. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 score of 8.2 reflects high confidentiality impact with a network attack vector, but the AT:P (Attack Target: Presence) metric and AC:H signal that specific prerequisites - pre-staged symlinked corpus files - must be satisfied before exploitation can occur. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | An attacker with write access to a shared NLTK corpus directory - for example, a low-privileged user on a multi-tenant NLP research server - creates a symbolic link inside the corpus folder pointing to a sensitive file outside the root, such as an application secrets file or /etc/shadow. When a legitimate downstream process invokes a corpus reader method such as synonyms() on that corpus, NLTK's affected reader calls Python's built-in open() on the symlink path, transparently follows the link, and returns the target file's contents to the caller. … |
| Remediation | The primary remediation is to upgrade NLTK to version 3.10.3 or later, which corrects the affected corpus readers to use nltk.pathsec.open() consistently throughout; the vendor advisory is at https://github.com/nltk/nltk/security/advisories/GHSA-p4rw-rvv2-7xwr. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, audit your infrastructure to identify all systems running NLTK and determine current versions, prioritizing production NLP pipelines and data processing systems. …
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Same weakness CWE-22 – Path Traversal
View allSame technique Path Traversal
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External POC / Exploit Code
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