Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck
CVE-2026-78680NLTK before 3.10.3 Arbitrary Code Execution via Graphviz dot Binary
High 7.8
In plain English
A high-severity security flaw in nltk from nltk. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
NLTK versions before 3.10.3 fail to use validated absolute paths when invoking the Graphviz dot binary in dependencygraph.dot2img and AlignedSent._repr_svg_, allowing attackers to execute arbitrary code by placing a malicious dot binary in the search path or current working directory. Attackers can exploit bare-name binary resolution on Windows via the current working directory or on Unix-like systems via relative PATH entries to execute their binary instead of the legitimate Graphviz tool.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nltk | no fix listed | DEBIAN-CVE-2026-78680 |
| Debian:13 | nltk | no fix listed | DEBIAN-CVE-2026-78680 |
| Debian:14 | nltk | 3.10.3-1 | DEBIAN-CVE-2026-78680 |
| PyPI | nltk | 3.10.3 | GHSA-6hwm-xvph-95vm |
| PyPI | nltk | 3.10.3 | PYSEC-2026-3868 |
Affected products (as reported)
Weakness: CWE-426 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- GitHub Security Advisory (GHSA-6hwm-xvph-95vm) vendor-advisory
- VulnCheck Advisory: NLTK before 3.10.3 Arbitrary Code Execution via Graphviz dot Binary third-party-advisory