Medium severity · published Aug 22, 2026
CVE-2026-70626
NLTK before 3.9.4 Symlink Escape via CorpusReader
6.2
CVSS
0.2%
EPSS
No
On KEV
Description
NLTK versions before 3.9.4 contain a symlink escape vulnerability in CorpusReader.open() that allows local attackers to read arbitrary files outside the corpus root. The vulnerability exists because path validation is lexical and does not account for symlink resolution, enabling attackers to place symlinks inside the corpus root to access files outside the intended boundary.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Local
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 10% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NL
nltk · nltk
before 3.9.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-70626
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-70626
Exploit
https://github.com/nltk/nltk/security/advisories/GHSA-r6gq-whwq-mvg9
Vendor Advisory
https://www.vulncheck.com/advisories/nltk-before-symlink-escape-via-corpusreader
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