CVE-2026-78680 NLTK before 3.10.3 Arbitrary Code Execution via Graphviz dot Binary
Attackers can execute arbitrary code by placing a malicious Graphviz binary in the search path, affecting NLTK users.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-78680?
CVE-2026-78680 is a high-severity command injection vulnerability in nltk, published on 25 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
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.
Weakness: CWE-426
Which versions are affected by CVE-2026-78680?
3 open source packages ship an affected version, including nltk.
| Package | Affected | Fixed in |
|---|---|---|
nltk PyPI | All versions | 3.10.3 |
nltk PyPI | All versions | 3.10.3 |
nltk PyPI | All versions | 3.10.3 |
How do I fix CVE-2026-78680?
Upgrade nltk to 3.10.3 or later.
Upgrade, and pass arguments to programs as a list instead of through a shell. More about Command injection.
Is CVE-2026-78680 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-78680 exists.
Sources
Also known as DEBIAN-CVE-2026-78680, ECHO-54ff-3814-cf1f, GHSA-6hwm-xvph-95vm, MINI-2v44-pxwv-4639, PYSEC-2026-3868.