Description
In nltk/nltk versions 3.9.3 and earlier, five Stanford interface classes (StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser) are vulnerable to untrusted JAR code execution. These classes accept user-controllable JAR paths and execute them via the `java()` function, which invokes `subprocess.Popen()` without integrity verification. This vulnerability is identical to CVE-2026-0848, which was fixed for StanfordSegmenter by adding SHA256 verification. However, the fix was not applied to these additional classes, leaving them susceptible to arbitrary code execution when loading untrusted JAR files.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nltk | nltk/nltk | unspecified – ≤ latest | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | nltk | 3.10.3-1 | — |
| Debian 13 | nltk | No fix yet | — |
| Debian 12 | nltk | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | nltk | No fix yet | — |
| Ubuntu 25.10 | nltk | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 24.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 22.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 20.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 18.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 16.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 14.04 LTS | nltk | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-nltk | 3.10.3-1.1 | openSUSE-SU-2026:11587-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | nltk | < 3.9.4 | 3.9.4 | GHSA-9r6g-266r-89x4 |
Advisories 1
- openSUSE-SU-2026:11587-1 python313-nltk-3.10.3-1.1 on GA media SUSE / openSUSE Security Updates · Aug 26, 2026