EUVD-2026-64336
GHSA-8vh5-mgjj-w6hg
Severity by source
CVSS:4.0/AV:N/AC:L/AT:N/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
Pickle deserialization enables arbitrary code execution beyond the NLTK process scope (S:C) with full C/I/A impact; PR:N because no authentication is required to bypass the disabled enforcement layer.
Primary rating from Vendor (VulnCheck).
CVSS VectorVendor: VulnCheck
Lifecycle Timeline
3Blast 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 3.10.0 default to ENFORCE=False in pathsec.py, causing all security validation functions to emit warnings instead of raising exceptions. Attackers can bypass path traversal and pickle deserialization protections by exploiting the disabled security controls that are only active when manually enabled.
AnalysisAI
Path traversal and pickle deserialization protections in NLTK before 3.10.0 are effectively disabled by default - pathsec.py sets ENFORCE=False, causing all security validation to emit warnings rather than raise blocking exceptions. Any application using NLTK to process untrusted file paths or serialized data is exposed unless operators have explicitly overridden this default. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | Exploitation requires that the target NLTK application processes attacker-controlled file paths or serialized pickle data through pathsec.py validation functions, and that the application has not explicitly overridden the default ENFORCE=False by setting it to True. … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 4.0 base score of 8.7 with AV:N/AC:L/AT:N/PR:N/UI:N reflects that network-accessible NLTK applications require no authentication and no special attack preconditions. … 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 to NLTK 3.10.0 or later, which is the vendor-confirmed patched release per GitHub Security Advisory GHSA-p3m8-78j2-g5p3 (https://github.com/nltk/nltk/security/advisories/GHSA-p3m8-78j2-g5p3). … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all systems and applications using NLTK and document current versions. …
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Same technique Deserialization
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