Staging Environment: Content and features may be unstable or change without notice.
Advisory details: gitlab / pypi/nltk/CVE-2026-54293
Advisory ID gitlab/pypi/nltk/CVE-2026-54293
Aliases CVE-2026-54293
GHSA-p4gq-832x-fm9v
Summary Natural Language Toolkit (NLTK): URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read nltk.data.load() in NLTK is vulnerable to path traversal via URL-encoded path separators and traversal segments when using the nltk: URL scheme. The unsafe-path regex check is performed before url2pathname() decodes the %xx sequences (a classic decode-after-check / TOCTOU-style flaw), allowing an attacker to bypass the protection documented in NLTK's SECURITY.md and read arbitrary files from the filesystem. While literal traversal strings such as ../../../etc/passwd are correctly blocked, encoded variants such as %2fetc%2fpasswd, %2e%2e%2f..., and ..%2f..%2f slip past the regex and are subsequently decoded into a real filesystem path.
Status Published
Exploitability 0.5
Weighted Severity 0.0
Risk
Affected and Fixed Packages Package Details
Introduced and Fixed Package Commit Patches Package Commit Patches Details
Weaknesses (3)
CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3.1 https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-54293.yml
Reference id Reference type URL
https://access.redhat.com/errata/RHSA-2026:42644
https://access.redhat.com/security/cve/CVE-2026-54293
https://bugzilla.redhat.com/show_bug.cgi?id=2491486
https://github.com/nltk/nltk/pull/3575
https://github.com/nltk/nltk/security/advisories/GHSA-p4gq-832x-fm9v
https://github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-2078.yaml
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54293.json
CVE-2026-54293 https://nvd.nist.gov/vuln/detail/CVE-2026-54293
GHSA-p4gq-832x-fm9v https://github.com/advisories/GHSA-p4gq-832x-fm9v
No exploits are available.

No EPSS data available for this advisory.

Patch URL
There are no known patches.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Found at https://gitlab.com/gitlab-org/advisories-community/-/blob/main/pypi/nltk/CVE-2026-54293.yml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: SSVCv2/E:P/A:Y/T:P/P:M/B:A/M:M/D:T/2026-06-22T21:18:34Z/

Decision: Track

Source URL: https://github.com/cisagov/vulnrichment/blob/develop/2026/54xxx/CVE-2026-54293.json

Source Advisory: vulnrichment/CVE-2026-54293

View SSVC decision tree 
[{'Exploitation': 'poc'},
 {'Automatable': 'yes'},
 {'Technical Impact': 'partial'},
 {'Mission Prevalence': 'minimal'},
 {'Public Well-being Impact': 'material'},
 {'Mission & Well-being': 'medium'}]