High severity · published Jun 17, 2026
CVE-2026-12199
Unauthenticated Denial of Service in nltk.app.wordnet_app
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NL
nltk/nltk · nltk
through latest · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-12199
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-12199
huntr.com
https://huntr.com/bounties/cee4ca6a-d17f-4746-abad-c68119633d37
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