Vulnerability · Published Aug 22, 2026 · Assigned by VulnCheck

CVE-2026-65915NLTK before 3.10.0 Arbitrary File Read via FileSystemPathPointer

Medium 6.5

In plain English

A medium-severity improper access control in nltk from nltk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium

Exploit odds (30 days)0.4%top 64.5% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

NLTK versions before 3.10.0 contain a logic bug in FileSystemPathPointer.open() where the sandbox validation check compares a normalized path against itself, making the security check permanently inert. Attackers can pass file:// URLs to nltk.data.load() to read arbitrary files accessible to the process user, including credentials and configuration files.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	nltk	no fix listed	DEBIAN-CVE-2026-65915
Debian:13	nltk	no fix listed	DEBIAN-CVE-2026-65915
Debian:14	nltk	3.10.0-1	DEBIAN-CVE-2026-65915
PyPI	nltk	3.10.0	GHSA-72r2-7mfr-5xr9
PyPI	nltk	3.10.0	PYSEC-2026-3731
Ubuntu:26.10	nltk	no fix listed	UBUNTU-CVE-2026-65915

Affected products (as reported)

Vendor	Product	Versions
nltk	nltk	0 – before 3.10.0

Weakness: CWE-284 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

References

GitHub Security Advisory (GHSA-72r2-7mfr-5xr9) vendor-advisory
VulnCheck Advisory: NLTK before 3.10.0 Arbitrary File Read via FileSystemPathPointer third-party-advisory