CVE•Published 2026-08-25•Modified 2026-09-01•0 articles on news•5 live references•NVD data

CVE-2026-78681Nltk · Nltk

Vulnerability data via NVD (ingested)

CVSS v3.1

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS percentile

Exploit Prediction Scoring System · top 80% of all CVEs

Weaknesses (CWE)

CWE-776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')

Description

NLTK versions before 3.10.3 use xml.etree.ElementTree to parse XML in multiple modules, which honors entity declarations in document DTDs. Attackers can craft XML payloads with nested entity declarations that expand from hundreds of bytes to megabytes in memory, causing denial of service.

Timeline

Published 2026-08-25

Modified 2026-09-01

External references

NVD MITRE Exploit-DB trickest/cve VulnCheck

Search for exposed instances

Shodan + Censys queries derived from NVD's CPE data. The vuln tag catches assets Shodan has explicitly linked to this CVE; the product / banner fingerprints find exposed instances even when the vuln tag was never applied (which is common).

Shodan · vuln tag0 hosts

vuln:CVE-2026-78681

Hosts Shodan has explicitly fingerprinted as vulnerable.

Shodan · product

product:"Nltk Nltk"

All exposed Nltk Nltk instances — cross-reference with the CVE's affected-version range.

Shodan · banner/body mention

http.html:"Nltk"

HTTP body or banner mentions "Nltk" — catches deploys Shodan didn't identify as a product.

More intel sources (5)

Shodan report

vuln:CVE-2026-78681