CVE-2026-12252
Untrusted JAR Code Execution in Multiple Stanford Interface Classes in nltk/nltk
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.8
Untrusted JAR Code Execution in Multiple Stanford Interface Classes in nltk/nltk
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.
- Record
CVE-2026-12252- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
EUVDEUVD-2026-41656
7.8
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.
- Record
EUVD-2026-41656- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9r6g-266r-89x4
7.8
NLTK Stanford wrapper classes execute untrusted JAR files without verification
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.
- Record
GHSA-9r6g-266r-89x4- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
NVD
7.8
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.
- Record
CVE-2026-12252- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
OSV
7.8
Untrusted JAR Code Execution in Multiple Stanford Interface Classes in nltk/nltk
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.
- Record
CVE-2026-12252- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-12252
7.8
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.
- Record
DEBIAN-CVE-2026-12252- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 4 moreShow less
OSVGHSA-9r6g-266r-89x4
7.8
NLTK Stanford wrapper classes execute untrusted JAR files without verification
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.
- Record
GHSA-9r6g-266r-89x4- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
OSVPYSEC-2026-2085
7.8
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.
- Record
PYSEC-2026-2085- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-12252
7.8
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.
- Record
UBUNTU-CVE-2026-12252- CVSS 3.0
- 7.8 High
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVopenSUSE-SU-2026:11587-1 No score
python313-nltk-3.10.3-1.1 on GA media
These are all security issues fixed in the python313-nltk-3.10.3-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2026:11587-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
nltkPyPI |
before 3.9.4 | 3.9.4 |
nltkDebian:12 |
All versions, plus listed versions 3.10.0-13.10.1-13.10.3-13.8-13.8.1-1 Show 4 moreShow less3.9.1-13.9.1-23.9.2-13.9.3-1 |
None known |
nltkDebian:13 |
All versions, plus listed versions 3.10.0-13.10.1-13.10.3-13.9.1-23.9.2-13.9.3-1 |
None known |
nltkDebian:14 |
before 3.10.3-1, plus listed versions 3.10.0-13.10.1-13.9.1-23.9.2-13.9.3-1 |
3.10.3-1 |
nltkPyPI |
before 3.9.4, plus listed versions 0.80.90.9.30.9.40.9.5 Show 45 moreShow less0.9.60.9.70.9.80.9.92.0.12.0.1rc12.0.1rc2-git2.0.1rc32.0.1rc42.0.22.0.32.0.42.0.52.0b42.0b52.0b62.0b72.0b82.0b93.0.03.0.0b13.0.0b23.0.13.0.23.0.33.0.43.0.53.13.23.2.13.2.23.2.33.2.43.2.53.33.43.4.13.4.23.4.33.4.43.4.53.53.5b13.63.6.1 |
3.9.4 |
nltkUbuntu:Pro:14.04:LTS |
All versions, plus listed versions 2.0~b9-0ubuntu42.0~b9-0ubuntu4.1~esm22.0~b9-0ubuntu4.1~esm42.0~b9-0ubuntu4.1~esm52.0~b9-0ubuntu4.1~esm6 |
None known |
nltkUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 3.0.4-13.0.5-13.1-13.1-1ubuntu0.13.1-1ubuntu0.1+esm13.1-1ubuntu0.1+esm23.1-1ubuntu0.1+esm33.1-1ubuntu0.1+esm4 |
None known |
nltkUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 3.2.4-13.2.5-13.2.5-1ubuntu0.13.2.5-1ubuntu0.1+esm13.2.5-1ubuntu0.1+esm23.2.5-1ubuntu0.1+esm33.2.5-1ubuntu0.1+esm4 |
None known |
nltkUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 3.4.5-13.4.5-23.4.5-2ubuntu0.1~esm13.4.5-2ubuntu0.1~esm23.4.5-2ubuntu0.1~esm33.4.5-2ubuntu0.1~esm4 |
None known |
nltkUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 3.5-13.6.5-13.6.7-13.7-13.7-1ubuntu0.1~esm13.7-1ubuntu0.1~esm2 |
None known |
Show 5 moreShow less
| Package | Affected | Fixed |
|---|---|---|
nltkUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 3.8.1-13.8.1-1ubuntu0.1~esm13.8.1-1ubuntu0.1~esm2 |
None known |
nltkUbuntu:25.10 |
All versions, plus listed versions 3.9.1-2 |
None known |
nltkUbuntu:26.10 |
All versions, plus listed versions 3.9.2-13.9.3-13.10.0-13.10.1-13.10.3-1 |
None known |
nltkUbuntu:Pro:26.04:LTS |
All versions, plus listed versions 3.9.1-23.9.1-2build13.9.2-13.9.2-1ubuntu0.1~esm13.9.2-1ubuntu0.1~esm2 |
None known |
python-nltkopenSUSE:Tumbleweed From an advisory covering 2 CVEs |
before 3.10.3-1.1 | 3.10.3-1.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, facts | ||
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-12252 is a high vulnerability (CVSS 7.8) in Nltk, published July 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.19%, the 9th percentile. Fixed in nltk 3.9.4.
References
huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb
nvd.nist.gov/vuln/detail/CVE-2026-12252
github.com/nltk/nltk/pull/3743
github.com/nltk/nltk/commit/006f4b83d430147b067b81e2cddd226d6fa405c8
github.com/nltk/nltk/commit/24777f0cb8c33ed2839d16e0f8169a3c312a6806
github.com/nltk/nltk/releases/tag/v3.10.3
Show 9 moreShow less
github.com/pypa/advisory-database/tree/main/vulns/nltk/PYSEC-2026-2085.yaml
github.com/advisories/GHSA-9r6g-266r-89x4
github.com/CVEProject/cvelistV5/tree/main/cves/2026/12xxx/CVE-2026-12252.json
security-tracker.debian.org/tracker/CVE-2026-12252
github.com/nltk/nltk
ubuntu.com/security/CVE-2026-12252
cve.org/CVERecord?id=CVE-2026-12252
suse.com/security/cve/CVE-2026-12252
suse.com/security/cve/CVE-2026-71513
Left out here: 14 versions. The JSON record has them.