CVE-2026-12199 Unauthenticated Denial of Service in nltk.app.wordnet_app
Unauthenticated attackers can remotely shut down the local WordNet Browser HTTP server by sending a specific GET request, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-12199?
CVE-2026-12199 is a high-severity denial of service vulnerability in nltk/nltk, published on 17 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
A vulnerability in `nltk.app.wordnet_app` up to version 3.9.3 allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when started in its default mode. The server listens on all interfaces and processes a specific unauthenticated GET request (`/SHUTDOWN%20THE%20SERVER`) to terminate the process immediately via `os._exit(0)`. This results in a denial of service, impacting service availability. The issue arises due to insufficient authentication and protection mechanisms for critical server functions.
Weakness: CWE-306
Which versions are affected by CVE-2026-12199?
How do I fix CVE-2026-12199?
No fix has been published for CVE-2026-12199 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-12199 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-12199 exists.
Sources
Also known as DEBIAN-CVE-2026-12199, GHSA-7jvr-hv34-f3rw, UBUNTU-CVE-2026-12199.