CVE-2026-54293 NLTK: URL-Encoded Path Traversal in nltk.data.load() Allows Arbitrary Local File Read
Attackers can read arbitrary local files by bypassing path traversal checks in nltk.data.load() using URL-encoded sequences.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-54293?
CVE-2026-54293 is a high-severity path traversal vulnerability in nltk, published on 22 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-22
Which versions are affected by CVE-2026-54293?
3 open source packages ship an affected version, including nltk. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
nltk PyPI | All versions | 3.10.0 |
nltk PyPI | All versions | 3.10.0 |
nltk PyPI | All versions | 3.10.0 |
Linux distribution packages (1)
python-nltk openSUSE:Tumbleweed | All versions | 3.10.0rc1-1.1 |
Products include Nltk Nltk.
How do I fix CVE-2026-54293?
Upgrade nltk to 3.10.0 or later.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-54293 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54293 exists.
Other vulnerabilities in nltk
- CVE-2026-0848 Arbitrary Code Execution in NLTK StanfordSegmenter via Untrusted JAR Loading
- CVE-2025-14009 Zip Slip Vulnerability in nltk/nltk Leading to Remote Code Execution
- CVE-2026-78683 NLTK before 3.10.0 Remote Code Execution via Unsafe Pickle Deserialization
- CVE-2026-79657 NLTK before 3.10.3 Remote Code Execution via Unsafe Pickle Deserialization
- CVE-2026-79675 NLTK before 3.10.3 JVM Argument Injection via Per-Call Options
Sources
Also known as DEBIAN-CVE-2026-54293, ECHO-c124-c77b-21c5, GHSA-p4gq-832x-fm9v, MGASA-2026-0281, MINI-q3j8-72fp-8x53, PYSEC-2026-2078 and 2 more.