7.5highHigh
CVE-2026-78681
Nltk Nltk
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.
Exploitation status
- Published references include exploit or proof-of-concept material. There is no confirmation it is being used in real attacks.
- A vendor advisory or patch reference has been published.
What the metrics mean
- It is reachable over a network, without needing local access.
- For an attacker who can reach it, no special conditions are needed to exploit it.
- To exploit it, no account is needed.
- Beyond that, no action by a user is required.
Scoring
- CVSS
- 7.5 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- CVSS v4
- 8.7
- Weakness
- CWE-776
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-08-25
- Last modified
- 2026-09-01
- Sources
- NVD
Affected products
- Nltk Nltk- 3.10.3
As listed in the NVD configuration data. Not a statement about your estate.