7.5

CVE-2026-12199: nltk nltk/nltk

CVSS: 7.5v3.0HighDeferred
AliasesUBUNTU-CVE-2026-12199DEBIAN-CVE-2026-12199
Published 17-06-2026Last modified 17-06-2026
Open JSON

Vulnerability summary

CVE-2026-12199 is a high (CVSS 7.5) vulnerability in nltk nltk/nltk. EPSS estimates a 0.33% chance of exploitation in the next 30 days, higher than 24.1% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.0 (CVE.org)
EPSS score
0.33%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 17-06-2026
    PublishedVulnerability first disclosed.
  2. 17-06-2026
    Last modifiedVulnerability information updated.

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 metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.33%

Chance of exploitation in the next 30 days

Percentile

24%

Versus all other CVEs

30-day change

0.00 pp

From 0.33% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.33%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Debian1 product
  • nltkAll versions (No fix recorded)
Nltk1 product
Ubuntu1 product
  • nltkAll versions (No fix recorded)

3 vendors · 3 products

References

4 links