NLTK before 3.10.4 contains a denial of service vulnerability in Tree.chomsky_normal_form that allows remote attackers to exhaust CPU through quadratic-time right-factor binarization using list.pop(0). Attackers can supply a wide flat treebank tree parsed by Tree.fromstring to force tens of seconds of single-threaded CPU consumption, blocking the processing thread.
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-r53h-rw34-8h97 | NLTK: Quadratic-time CPU denial of service in Tree.chomsky_normal_form right-factor binarization via list.pop(0) |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 13 Nov 2026 09:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | NLTK before 3.10.4 contains a denial of service vulnerability in Tree.chomsky_normal_form that allows remote attackers to exhaust CPU through quadratic-time right-factor binarization using list.pop(0). Attackers can supply a wide flat treebank tree parsed by Tree.fromstring to force tens of seconds of single-threaded CPU consumption, blocking the processing thread. | |
| Title | NLTK before 3.10.4 Quadratic CPU Denial of Service via Tree.chomsky_normal_form | |
| First Time appeared |
Nltk
Nltk nltk |
|
| Weaknesses | CWE-400 | |
| CPEs | cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Nltk
Nltk nltk |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-11-13T22:30:00.165Z
Reserved: 2026-11-10T20:15:54.612Z
Link: CVE-2026-126298
No data.
Status : Awaiting Analysis
Published: 2026-11-13T10:17:34.580
Modified: 2026-11-13T23:17:16.267
Link: CVE-2026-126298
No data.
OpenCVE Enrichment
Updated: 2026-11-14T14:45:22Z
Weaknesses
Github GHSA