Vulnerability · Published Jun 22, 2026 · Assigned by GitHub_M

CVE-2026-54293NLTK: URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read

High 7.5

In plain English

A high-severity path traversal in nltk from nltk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 51% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)7.5High

Exploit odds (30 days)0.6%top 49.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. Prior to 3.10.0-rc1, 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. This vulnerability is fixed in 3.10.0-rc1.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	nltk	no fix listed	DEBIAN-CVE-2026-54293
Debian:13	nltk	no fix listed	DEBIAN-CVE-2026-54293
Debian:14	nltk	3.10.0-1	DEBIAN-CVE-2026-54293
PyPI	nltk	3.10.0	PYSEC-2026-2078
PyPI	nltk	3.10.0	GHSA-p4gq-832x-fm9v
Ubuntu:25.10	nltk	no fix listed	UBUNTU-CVE-2026-54293
Ubuntu:26.10	nltk	no fix listed	UBUNTU-CVE-2026-54293

Affected products (as reported)

Vendor	Product	Versions
nltk	nltk	< 3.10.0-rc1

Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/nltk/nltk/security/advisories/GHSA-p4gq-832x-fm9v x_refsource_CONFIRM
https://github.com/nltk/nltk/pull/3575 x_refsource_MISC
https://access.redhat.com/security/cve/CVE-2026-54293 vdb-entry, x_refsource_REDHAT
RHBZ#2491486 issue-tracking, x_refsource_REDHAT
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-54293.json x_sadp-csaf-vex
https://access.redhat.com/errata/RHSA-2026:42644 vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:65126 vendor-advisory, x_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:60520 vendor-advisory, x_refsource_REDHAT