CVE-2026-12252 Details
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.
A vulnerability allowing untrusted JAR code execution has been identified in nltk/nltk versions 3.9.3 and earlier. This issue affects five Stanford interface classes: StanfordPOSTagger, StanfordNERTagger, StanfordParser, StanfordDependencyParser, and StanfordNeuralDependencyParser. These classes accept user-controlled JAR paths and execute them via the 'java()' function, which calls 'subprocess.Popen()' without proper integrity verification. This vulnerability mirrors CVE-2026-0848, which was addressed for StanfordSegmenter by introducing SHA256 verification, a fix that was not extended to the other classes, leaving them open to arbitrary code execution when untrusted JAR files are loaded.
Users are advised to update to nltk version 3.9.4 or later, where this vulnerability has been fixed by adding the necessary SHA256 verification for the affected Stanford interface classes.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 6, 2026References to Advisories, Solutions, and Tools
By selecting these links, you will be leaving this site. These are references gathered from the official CVE record and are not endorsed by Volerion.
| URL | Source(s) | Tag(s) |
|---|---|---|
| https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb | CISA-ADP | ExploitThird Party Advisory |
| https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb | [email protected] | ExploitThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-94 | Improper Control of Generation of Code ('Code Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| nltk nltk | <= 3.9.3 |
CPE
Remediation
| |
Change History
3 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 8, 2026 | Initial Analysis | [email protected] |
| Jul 6, 2026 | CVE Modified | CISA-ADP |
| Jul 4, 2026 | New CVE Received | [email protected] |