{"document":{"category":"csaf_vex","csaf_version":"2.0","title":"CVE-2026-12199: Unauthenticated Denial of Service in nltk.app.wordnet_app","publisher":{"category":"vendor","name":"HarborGuard Database","namespace":"https://database.harborguard.co"},"tracking":{"id":"CVE-2026-12199","status":"final","version":"1","initial_release_date":"2026-06-17T07:13:14.977Z","current_release_date":"2026-06-17T07:13:14.977Z","revision_history":[{"date":"2026-06-17T07:13:14.977Z","number":"1","summary":"Initial machine-readable export from HarborGuard."}]},"distribution":{"tlp":{"label":"WHITE"},"text":"Public CVE data; freely redistributable."},"notes":[{"category":"description","text":"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.","title":"CVE description"}],"references":[{"category":"self","summary":"CVE-2026-12199 on HarborGuard Database","url":"https://database.harborguard.co/cve/CVE-2026-12199"},{"category":"external","summary":"CVE Record","url":"https://www.cve.org/CVERecord?id=CVE-2026-12199"},{"category":"external","summary":"huntr.com","url":"https://huntr.com/bounties/cee4ca6a-d17f-4746-abad-c68119633d37"}]},"product_tree":{"branches":[{"category":"vendor","name":"nltk","branches":[{"category":"product_name","name":"nltk/nltk","branches":[{"category":"product_version_range","name":">=unspecified <=latest","product":{"name":"nltk nltk/nltk >=unspecified <=latest","product_id":"CSAFPID-1","product_identification_helper":{"cpe":"cpe:2.3:a:nltk:nltk\\/nltk:*:*:*:*:*:*:*:*"}}}]}]}]},"vulnerabilities":[{"cve":"CVE-2026-12199","title":"Unauthenticated Denial of Service in nltk.app.wordnet_app","notes":[{"category":"description","text":"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.","title":"CVE description"}],"product_status":{"known_affected":["CSAFPID-1"]},"scores":[{"cvss_v3":{"version":"3.0","vectorString":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"products":["CSAFPID-1"]}],"remediations":[{"category":"none_available","details":"No fixed version is published yet. Monitor the upstream advisory.","product_ids":["CSAFPID-1"]}]}]}