How severe is CVE-2026-33236?

CVE-2026-33236 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2026-33236 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-33236?

CVE-2026-33236 affects Nltk. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-33236?

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.

Does CVE-2026-33236 have an EU (EUVD) identifier?

Yes. CVE-2026-33236 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13887.

When was CVE-2026-33236 published?

CVE-2026-33236 was published on 2026-03-20 and last updated on 2026-07-21.

CVE-2026-33236

CVE-2026-33236 is a high-severity vulnerability in Nltk with a CVSS 3.x base score of 8.1. 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-22.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-13887
Weakness: CWE-22
Affected product: Nltk
Published: 2026-03-20
Last modified: 2026-07-21

Description

NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, the NLTK downloader does not validate the `subdir` and `id` attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as `../`), which can lead to arbitrary directory creation, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.

Frequently asked questions

What is CVE-2026-33236?: NLTK (Natural Language Toolkit) is a suite of open source Python modules, data sets, and tutorials supporting research and development in Natural Language Processing. In versions 3.9.3 and prior, the NLTK downloader does not validate the `subdir` and `id` attributes when processing remote XML index files. Attackers can control a remote XML index server to provide malicious values containing path traversal sequences (such as `../`), which can lead to arbitrary directory creation, arbitrary file creation, and arbitrary file overwrite. Commit 89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a patches the issue.
How severe is CVE-2026-33236?: CVE-2026-33236 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2026-33236 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33236?: CVE-2026-33236 affects Nltk. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33236?: 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.
Does CVE-2026-33236 have an EU (EUVD) identifier?: Yes. CVE-2026-33236 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13887.
When was CVE-2026-33236 published?: CVE-2026-33236 was published on 2026-03-20 and last updated on 2026-07-21.

References

Affected products (1)

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

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