How severe is CVE-2026-12252?

CVE-2026-12252 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-12252 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-12252?

CVE-2026-12252 affects Nltk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-12252?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2026-12252 published?

CVE-2026-12252 was published on 2026-07-04 and last updated on 2026-07-08.

CVE-2026-12252

CVE-2026-12252 is a high-severity vulnerability in Nltk with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-94.

Key facts

Severity: High (CVSS 3.x base score 7.8)
EPSS exploit prediction: 0% (5th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-94
Affected product: Nltk
Published: 2026-07-04
Last modified: 2026-07-08

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.

Frequently asked questions

What is CVE-2026-12252?: 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.
How severe is CVE-2026-12252?: CVE-2026-12252 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-12252 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (5th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-12252?: CVE-2026-12252 affects Nltk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-12252?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2026-12252 published?: CVE-2026-12252 was published on 2026-07-04 and last updated on 2026-07-08.

References

https://huntr.com/bounties/f5c93982-0cc9-4e2e-bb85-1b6ab29a2efb

Affected products (1)

cpe:2.3:a:nltk:nltk:*:*:*:*:*:*:*:*

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