CVE-2026-81727
NLTK before 3.10.3 Hardlink File Overwrite via downloader
Description
NLTK versions before 3.10.3 contain a filesystem containment bypass vulnerability in the Downloader.download and Downloader.incr_download methods that allows attackers to overwrite files outside the install root through pre-existing hardlinks. Attackers with write access to a shared downloader directory can create hardlinks pointing to outside-root files that are then overwritten during normal package extraction, mutating files outside the intended install tree.
CVSS Vector Breakdown
AV:LAttack VectorAC:LAttack ComplexityPR:LPrivileges RequiredUI:NUser InteractionS:UScopeC:NConfidentialityI:HIntegrityA:HAvailabilityWeaknesses
Affected Products
Exploitability
Attack Graph
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MITRE ATT&CK
2 techniquesReferences
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