CVE-2026-33236

HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence

Score 8.1 from GitHub Security Advisory (severity: HIGH) published 2026-03-19. a secondary CVSS source baseline 8.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.1Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
8.1
EG Score
8.1(medium)
EPSS
38.4%
KEV
Not listed

Published

March 20, 2026

Last Modified

June 30, 2026

Advisory Details (7)

Auto-updated Jun 30, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github, redhat.
redhat
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33236.json
redhat

2449824 – (CVE-2026-33236) CVE-2026-33236 nltk: NLTK: Arbitrary file overwrite and creation via path traversal in XML index files

https://bugzilla.redhat.com/show_bug.cgi?id=2449824
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-33236
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:19712
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:10184
github Patch Available🟡 PoC Available

Downloader Path Traversal Vulnerability (AFO) - Arbitrary File Overwrite · Advisory · nltk/nltk · GitHub

https://github.com/nltk/nltk/security/advisories/GHSA-469j-vmhf-r6v7
github_commit Patch Available

commit 89fe2ec2c6ba (nltk/nltk)

Patch available: nltk/nltk v3.10.0-rc1 (contains commit 89fe2ec2c6ba)

https://github.com/nltk/nltk/commit/89fe2ec2c6bae6e2e7a46dad65cc34231976ed8a

Vendor Advisories for CVE-2026-33236(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(4)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntupython3-nltk (3.4.5-2ubuntu0.1~esm4) @ focal2026-06-30ubuntu
redhatrhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9:17782630542026-05-20redhat
redhatrhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9:17763191852026-04-23redhat
pipnltk—ghsa

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 8× in last 7d / 12× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-06 16:27 UTCEPSS rescore
  2. 2026-07-06 16:27 UTCEPSS rescore
  3. 2026-07-06 02:23 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-01 15:06 UTCEPSS rescore
  8. 2026-06-30 23:22 UTCEPSS rescore
  9. 2026-06-30 04:37 UTCEG score recompute
  10. 2026-06-30 04:37 UTCVendor advisory
  11. 2026-06-30 04:37 UTCGHSA enrichment
  12. 2026-06-30 04:32 UTCNVD updatefirst tracked

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-33236?
CVE-2026-33236 is a high vulnerability published on March 20, 2026. 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…
When was CVE-2026-33236 disclosed?
CVE-2026-33236 was first published in the National Vulnerability Database on March 20, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33236 actively exploited?
CVE-2026-33236 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 38.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-33236?
CVE-2026-33236 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-33236?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33236, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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