What’s Vulnerable › Vulnerabilities

CVE-2026-12199: Unauthenticated Denial of Service in nltk.app.wordnet_app

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-17 · updated 2026-06-17
• Weakness: CWE-306

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.

Affected products

• nltk: through latest

References

• https://huntr.com/bounties/cee4ca6a-d17f-4746-abad-c68119633d37
• https://huntr.com/bounties/cee4ca6a-d17f-4746-abad-c68119633d37

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