Bug 2489776 (CVE-2026-12199)

Summary: CVE-2026-12199 nltk: NLTK: Remote unauthenticated denial of service in WordNet Browser HTTP server
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: anpicker, bparees, dschmidt, erezende, hasun, jfula, jkoehler, jlanda, jowilson, jwong, kshier, lphiri, nyancey, omaciel, ometelka, ptisnovs, simaishi, smcdonal, stcannon, syedriko, teagle, xdharmai, yguenane
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the `nltk` component, specifically in the `nltk.app.wordnet_app`. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted GET request to the WordNet Browser HTTP server when it is running in its default mode. This allows the attacker to immediately shut down the server, leading to a denial of service (DoS) and impacting service availability. The issue stems from insufficient authentication and protection mechanisms for critical server functions.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-06-17 08:01:26 UTC
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.