CVE-2026-33231

HIGHPre-NVD 7.57.5—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.5 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.9%, top 43% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.5%CVSS: 7.5Exploit: Elevated riskExposed services: Not assessed

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, nltk.app.wordnet_app allows unauthenticated remote shutdown of the local WordNet Browser HTTP server when it is started in its default mode. A simple GET /SHUTDOWN%20THE%20SERVER request causes the process to terminate immediately via os._exit(0), resulting in a denial of service. Commit bbaae83db86a0f49e00f5b0db44a7254c268de9b patches the issue.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
65
EG Risk 65/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity75% × 45%
Exploitation40% × 40%
Automatability100% × 15%
EPSS PROB
1.5%
EPSS %ILE
72nd
KEV
Not listed

Published

March 20, 2026

Last Modified

September 9, 2026

Advisory Details (7)

Auto-updated Jul 6, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github, redhat.
redhat
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33231.json
redhat

2449836 – (CVE-2026-33231) CVE-2026-33231 nltk: NLTK: Denial of Service via unauthenticated remote shutdown

https://bugzilla.redhat.com/show_bug.cgi?id=2449836
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-33231
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:24977
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:19712
github Patch Available🟡 PoC Available

Unauthenticated remote shutdown in nltk.app.wordnet_app · Advisory · nltk/nltk · GitHub

https://github.com/nltk/nltk/security/advisories/GHSA-jm6w-m3j8-898g
github_commit Patch Available

commit bbaae83db86a (nltk/nltk)

Patch available: nltk/nltk v3.10.0-rc1 (contains commit bbaae83db86a)

https://github.com/nltk/nltk/commit/bbaae83db86a0f49e00f5b0db44a7254c268de9b

Vendor Advisories for CVE-2026-33231(5)

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

Patch Availability(5)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntupython3-nltk (3.2.5-1ubuntu0.1+esm4) @ bionic2026-09-09ubuntu
redhatrhoai/odh-ta-lmes-job-rhel9:17873309032026-09-08redhat
redhatrhoai/odh-trustyai-nemo-guardrails-server-rhel9:17824716062026-07-09redhat
redhatrhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9:17800692262026-06-10redhat
redhatrhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9:17782630542026-05-20redhat

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.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
nltk3.10.0-1 ... 3.9.3-1 (12 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
nltk3.10.0-1 ... 3.9.3-1 (9 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
nltk3.10.0-1 ... 3.9.3-1 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
nltk3.9.1-2, 3.9.2-1, 3.9.3-1
  • every version up to 3.10.0-1: fixed in 3.10.0-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
nltk0.8 ... 3.9b1 (64 versions)
  • every version up to 3.9.4: fixed in 3.9.4
—

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 5× in last 7d / 28× 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.

Showing the most recent 100 of 133 total refreshes for this CVE.

  1. 2026-10-05 17:42 UTCEPSS rescore
  2. 2026-10-03 14:25 UTCEPSS rescore
  3. 2026-10-01 19:49 UTCEPSS rescore
  4. 2026-09-30 15:03 UTCEPSS rescore
  5. 2026-09-29 07:15 UTCOSV refresh
  6. 2026-09-28 13:51 UTCEPSS rescore
  7. 2026-09-27 13:48 UTCEPSS rescore
  8. 2026-09-26 15:58 UTCEPSS rescore
  9. 2026-09-26 00:26 UTCEPSS rescore
  10. 2026-09-20 20:15 UTCEPSS rescore
  11. 2026-09-18 19:28 UTCEPSS rescore
  12. 2026-09-18 19:28 UTCEPSS rescore
  13. 2026-09-17 19:30 UTCEPSS rescore
  14. 2026-09-16 14:08 UTCEPSS rescore
  15. 2026-09-16 05:15 UTCEPSS rescore
  16. 2026-09-15 03:11 UTCEPSS rescore
  17. 2026-09-13 16:47 UTCEPSS rescore
  18. 2026-09-12 15:01 UTCEPSS rescore
  19. 2026-09-11 14:52 UTCEPSS rescore
  20. 2026-09-10 09:34 UTCEPSS rescore
  21. 2026-09-09 13:42 UTCEG score recompute
  22. 2026-09-09 13:42 UTCVendor advisory
  23. 2026-09-09 12:41 UTCEG score recompute
  24. 2026-09-09 12:41 UTCVendor advisory
  25. 2026-09-08 22:00 UTCEPSS rescore
Show 75 more
  1. 2026-09-07 16:01 UTCEPSS rescore
  2. 2026-09-06 13:47 UTCEPSS rescore
  3. 2026-09-06 13:47 UTCEPSS rescore
  4. 2026-09-04 05:06 UTCEPSS rescore
  5. 2026-09-02 16:38 UTCOSV refresh
  6. 2026-09-02 14:11 UTCEPSS rescore
  7. 2026-09-01 13:53 UTCEPSS rescore
  8. 2026-09-01 04:39 UTCEPSS rescore
  9. 2026-09-01 04:39 UTCEPSS rescore
  10. 2026-08-30 19:17 UTCEPSS rescore
  11. 2026-08-30 01:22 UTCEPSS rescore
  12. 2026-08-28 21:41 UTCEPSS rescore
  13. 2026-08-27 14:25 UTCEPSS rescore
  14. 2026-08-26 14:46 UTCEPSS rescore
  15. 2026-08-25 13:49 UTCEPSS rescore
  16. 2026-08-24 14:17 UTCEPSS rescore
  17. 2026-08-23 00:19 UTCEPSS rescore
  18. 2026-08-21 23:49 UTCEPSS rescore
  19. 2026-08-20 22:55 UTCEPSS rescore
  20. 2026-08-20 22:55 UTCEPSS rescore
  21. 2026-08-19 17:03 UTCEPSS rescore
  22. 2026-08-18 13:48 UTCEPSS rescore
  23. 2026-08-16 14:56 UTCEPSS rescore
  24. 2026-08-16 10:59 UTCEG score recompute
  25. 2026-08-16 10:59 UTCVendor advisory
  26. 2026-08-16 02:14 UTCEPSS rescore
  27. 2026-08-15 01:30 UTCEPSS rescore
  28. 2026-08-14 19:53 UTCVendor advisory
  29. 2026-08-14 07:09 UTCEG score recompute
  30. 2026-08-14 07:09 UTCVendor advisory
  31. 2026-08-13 22:00 UTCEPSS rescore
  32. 2026-08-12 21:49 UTCEG score recompute
  33. 2026-08-12 21:49 UTCVendor advisory
  34. 2026-08-12 13:50 UTCEPSS rescore
  35. 2026-08-11 21:22 UTCEG score recompute
  36. 2026-08-11 21:22 UTCVendor advisory
  37. 2026-08-11 04:22 UTCEG score recompute
  38. 2026-08-11 04:22 UTCVendor advisory
  39. 2026-08-11 00:00 UTCEPSS rescore
  40. 2026-08-10 08:12 UTCVendor advisory
  41. 2026-08-09 19:27 UTCEG score recompute
  42. 2026-08-09 19:27 UTCVendor advisory
  43. 2026-08-09 13:46 UTCEPSS rescore
  44. 2026-08-09 06:43 UTCEG score recompute
  45. 2026-08-09 06:43 UTCVendor advisory
  46. 2026-08-08 16:37 UTCEPSS rescore
  47. 2026-08-08 05:56 UTCVendor advisory
  48. 2026-08-07 17:12 UTCEG score recompute
  49. 2026-08-07 17:12 UTCVendor advisory
  50. 2026-08-06 19:15 UTCEG score recompute
  51. 2026-08-06 19:15 UTCVendor advisory
  52. 2026-08-06 13:46 UTCEPSS rescore
  53. 2026-08-06 01:25 UTCEG score recompute
  54. 2026-08-06 01:25 UTCVendor advisory
  55. 2026-08-05 19:17 UTCEPSS rescore
  56. 2026-08-04 15:10 UTCEPSS rescore
  57. 2026-08-04 10:38 UTCEPSS rescore
  58. 2026-08-04 00:33 UTCEG score recompute
  59. 2026-08-04 00:33 UTCVendor advisory
  60. 2026-08-03 10:36 UTCEPSS rescore
  61. 2026-08-02 16:08 UTCEG score recompute
  62. 2026-08-02 16:08 UTCVendor advisory
  63. 2026-08-02 02:27 UTCEPSS rescore
  64. 2026-08-01 04:16 UTCEPSS rescore
  65. 2026-07-30 16:28 UTCEPSS rescore
  66. 2026-07-30 01:30 UTCEPSS rescore
  67. 2026-07-27 14:13 UTCEPSS rescore
  68. 2026-07-26 14:54 UTCEPSS rescore
  69. 2026-07-26 14:54 UTCEPSS rescore
  70. 2026-07-25 14:18 UTCEPSS rescore
  71. 2026-07-25 14:18 UTCEPSS rescore
  72. 2026-07-24 14:17 UTCEPSS rescore
  73. 2026-07-24 14:17 UTCEPSS rescore
  74. 2026-07-23 14:18 UTCEPSS rescore
  75. 2026-07-23 14:18 UTCEPSS rescore

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

Frequently asked(5)

What is CVE-2026-33231?
CVE-2026-33231 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, nltk.app.wordnetapp allows unauthenticated remote shutdown of the local WordNet Browser HTTP server…
When was CVE-2026-33231 disclosed?
CVE-2026-33231 was first published on March 20, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33231 actively exploited?
CVE-2026-33231 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.5% probability of exploitation in the next 30 days (72nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33231?
CVE-2026-33231 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-33231?
A fix for CVE-2026-33231 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33231 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-33231

Explore →

Is Your Infrastructure Affected by CVE-2026-33231?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.

Book a Demo →Browse All CVEs