CVE-2026-126299
NLTK before 3.10.4 contains a denial of service vulnerability in the CCG lexicon parser fromstring that allows remote attackers to exhaust CPU by supplying wide inputs. Attackers can submit lexicon text with long flat bracket bodies or operator chains, triggering quadratic string re-slicing in matchBrackets and augParseCategory that blocks worker threads.
- Score
- 8.7 high
- Published
- 2026-11-13
- Links
- NVD · cve.org · Report wrong data
Matched ports (1)
| Port | Package | Version | Status | Maintainer |
|---|---|---|---|---|
| textproc/py-nltk | py312-nltk | 3.10.0,2 | unaddressed | demon@FreeBSD.org |
Template for a VuXML entry
Check the version numbers before you commit this entry. Some ports share an entry in the CVE database with another port, such as sqlite2 and sqlite3. The version shown here may then be one that never existed for this port.
Ranges per package from the CVE rows that match this port, in pkg notation with the port's epoch and revision, every bound checked with pkg; one range per epoch the port actually had. make newentry in security/vuxml creates the vid.
<vuln vid="FIXME (make newentry)">
<topic>py312-nltk -- FIXME</topic>
<affects>
<package>
<name>py312-nltk</name>
<range><lt>3.10.4,2</lt></range>
</package>
</affects>
<description>
<body xmlns="http://www.w3.org/1999/xhtml">
<p>CVE-2026-126299: NLTK before 3.10.4 contains a denial of service
vulnerability in the CCG lexicon parser fromstring that allows
remote attackers to exhaust CPU by supplying wide inputs. Attackers
can submit lexicon text with long flat bracket bodies or operator
chains, triggering quadratic string re-slicing in matchBrackets and
augParseCategory that blocks worker threads.</p>
</body>
</description>
<references>
<cvename>CVE-2026-126299</cvename>
<url>https://nvd.nist.gov/vuln/detail/CVE-2026-126299</url>
</references>
<dates>
<discovery>2026-11-13</discovery>
<entry>2026-11-13</entry>
</dates>
</vuln>