EUVD-2026-64339
GHSA-343m-9fqq-97c7
Severity by source
CVSS:4.0/AV:L/AC:L/AT:N/PR:L/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
Local attack requiring write access to corpus directory drives AV:L and PR:L; no integrity or availability impact; scope unchanged as exploit stays within the process boundary.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
2Blast Radius
ecosystem impact- 7 pypi packages depend on nltk (6 direct, 1 indirect)
Ecosystem-wide dependent count for version 3.10.0.
DescriptionCVE.org
nltk versions before 3.10.2 contain a symlink-based arbitrary file read vulnerability in IPIPANCorpusReader methods that bypass nltk.pathsec validation entirely. Attackers can place a symlink in the corpus root directory and read arbitrary files accessible to the process by calling channels(), domains(), categories(), or fileids() methods with the symlink filename.
AnalysisAI
Symlink-based arbitrary file read in NLTK's IPIPANCorpusReader exposes files accessible to the running process on systems where untrusted local users can write to corpus root directories. Affected NLTK versions before 3.10.2 fail to follow symlinks through the nltk.pathsec validation layer when IPIPANCorpusReader methods - channels(), domains(), categories(), or fileids() - resolve filenames, allowing the symlink target to be read instead of the intended corpus file. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires three concrete preconditions: (1) the attacker has local write access to the specific filesystem directory configured as the NLTK corpus root for an IPIPANCorpusReader instance; (2) the target application instantiates IPIPANCorpusReader and invokes one of the vulnerable methods - channels(), domains(), categories(), or fileids() - during normal operation or in response to attacker-influenced input; (3) NLTK is running at version earlier than 3.10.2. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 vector (AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N) accurately characterizes the threat: local access is required, complexity is low once preconditions are met, and low OS-level privileges suffice if the attacker can write to the corpus directory. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | Upgrade NLTK to version 3.10.2 or later, which introduces proper symlink resolution and validation in IPIPANCorpusReader methods. … Detailed patch versions, workarounds, and compensating controls in full report. |
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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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