CVE-2026-71513

HIGHPre-NVD 8.88.8—
EchelonGraph scoreHIGH confidence

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-08-22. a secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
8.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 8.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft untrusted transition-parser models that execute arbitrary commands when TransitionParser.parse loads the model through allowlisted_pickle_load.

CVSS v3
8.8
EG Score
8.8(high)
EG Risk
40(Track)
EG Risk 40/100SSVC: Track

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
Severity88% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
55%
KEV
Not listed

Published

August 22, 2026

Last Modified

September 16, 2026

Advisory Details (4)

Auto-updated Aug 22, 2026
Patch available. Sources: github_commit.
generic

NLTK 3.10.0 through 3.10.2 Remote Code Execution via AllowlistUnpickler Dotted-Name Bypass | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nltk-through-remote-code-execution-via-allowlistunpickler-dotted-name-bypass
generic

nltk/nltk/picklesec.py at v3.10.2 · nltk/nltk · GitHub

https://github.com/nltk/nltk/blob/v3.10.2/nltk/picklesec.py#L119-L124
generic

GitHub - nltk/nltk: NLTK Source · GitHub

https://github.com/nltk/nltk
github_commit Patch Available

commit c3e37113742a (nltk/nltk)

Patch available: nltk/nltk v3.10.3-rc1 (contains commit c3e37113742a)

https://github.com/nltk/nltk/commit/c3e37113742a1ebeeb4f2ca58941f320f98805ea

Vendor Advisories for CVE-2026-71513(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0-1 ... 3.9.3-1 (9 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0-1 ... 3.9.3-1 (6 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0-1, 3.10.1-1, 3.9.1-2, 3.9.2-1, 3.9.3-13.10.3-1—
PyPI(1)
PackageVulnerable rangeFixed inDependents
nltk3.10.0, 3.10.1, 3.10.23.10.3—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 78× 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. 2026-09-19 00:03 UTCEG score recompute
  2. 2026-09-18 19:28 UTCEPSS rescore
  3. 2026-09-18 00:45 UTCEG score recompute
  4. 2026-09-17 01:13 UTCEG score recompute
  5. 2026-09-16 14:08 UTCEPSS rescore
  6. 2026-09-16 09:34 UTCEG score recompute
  7. 2026-09-16 05:15 UTCEPSS rescore
  8. 2026-09-15 09:49 UTCEG score recompute
  9. 2026-09-15 03:12 UTCEPSS rescore
  10. 2026-09-13 22:55 UTCEG score recompute
  11. 2026-09-12 23:45 UTCEG score recompute
  12. 2026-09-12 15:02 UTCEPSS rescore
  13. 2026-09-12 00:34 UTCEG score recompute
  14. 2026-09-11 14:53 UTCEPSS rescore
  15. 2026-09-11 12:58 UTCEG score recompute
  16. 2026-09-10 13:26 UTCEG score recompute
  17. 2026-09-10 09:35 UTCEPSS rescore
  18. 2026-09-09 01:42 UTCEG score recompute
  19. 2026-09-08 22:01 UTCEPSS rescore
  20. 2026-09-07 17:04 UTCEG score recompute
  21. 2026-09-06 17:53 UTCEG score recompute
  22. 2026-09-06 13:48 UTCEPSS rescore
  23. 2026-09-05 18:41 UTCEG score recompute
  24. 2026-09-04 19:30 UTCEG score recompute
  25. 2026-09-04 07:49 UTCEG score recompute
Show 53 more
  1. 2026-09-04 05:07 UTCEPSS rescore
  2. 2026-09-02 20:55 UTCEG score recompute
  3. 2026-09-02 14:12 UTCEPSS rescore
  4. 2026-09-02 07:46 UTCGHSA enrichment
  5. 2026-09-01 20:11 UTCEG score recompute
  6. 2026-09-01 20:11 UTCGHSA enrichment
  7. 2026-09-01 13:54 UTCEPSS rescore
  8. 2026-09-01 08:35 UTCEG score recompute
  9. 2026-09-01 08:35 UTCGHSA enrichment
  10. 2026-09-01 04:40 UTCEPSS rescore
  11. 2026-08-31 20:56 UTCGHSA enrichment
  12. 2026-08-31 17:55 UTCGHSA enrichment
  13. 2026-08-31 04:22 UTCEG score recompute
  14. 2026-08-31 04:22 UTCGHSA enrichment
  15. 2026-08-30 19:17 UTCEPSS rescore
  16. 2026-08-30 16:47 UTCGHSA enrichment
  17. 2026-08-30 05:12 UTCEG score recompute
  18. 2026-08-30 05:12 UTCGHSA enrichment
  19. 2026-08-30 01:22 UTCEPSS rescore
  20. 2026-08-29 17:36 UTCGHSA enrichment
  21. 2026-08-29 05:41 UTCEG score recompute
  22. 2026-08-29 05:40 UTCGHSA enrichment
  23. 2026-08-28 21:42 UTCEPSS rescore
  24. 2026-08-28 18:05 UTCGHSA enrichment
  25. 2026-08-28 05:16 UTCGHSA enrichment
  26. 2026-08-27 17:37 UTCEG score recompute
  27. 2026-08-27 17:37 UTCGHSA enrichment
  28. 2026-08-27 17:17 UTCEG score recompute
  29. 2026-08-27 17:17 UTCGHSA enrichment
  30. 2026-08-27 14:22 UTCGHSA enrichment
  31. 2026-08-27 02:46 UTCGHSA enrichment
  32. 2026-08-26 15:11 UTCEG score recompute
  33. 2026-08-26 15:11 UTCGHSA enrichment
  34. 2026-08-26 14:47 UTCEPSS rescore
  35. 2026-08-26 03:35 UTCGHSA enrichment
  36. 2026-08-25 15:59 UTCEG score recompute
  37. 2026-08-25 15:59 UTCGHSA enrichment
  38. 2026-08-25 13:49 UTCEPSS rescore
  39. 2026-08-25 04:23 UTCEG score recompute
  40. 2026-08-25 04:23 UTCGHSA enrichment
  41. 2026-08-25 04:10 UTCEG score recompute
  42. 2026-08-25 04:10 UTCGHSA enrichment
  43. 2026-08-25 00:19 UTCEG score recompute
  44. 2026-08-25 00:19 UTCGHSA enrichment
  45. 2026-08-24 12:43 UTCEG score recompute
  46. 2026-08-24 12:43 UTCGHSA enrichment
  47. 2026-08-24 01:08 UTCGHSA enrichment
  48. 2026-08-23 13:33 UTCGHSA enrichment
  49. 2026-08-23 01:57 UTCEG score recompute
  50. 2026-08-23 01:57 UTCGHSA enrichment
  51. 2026-08-22 14:22 UTCEG score recompute
  52. 2026-08-22 13:46 UTCEG score recompute
  53. 2026-08-22 13:45 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-71513?
CVE-2026-71513 is a high vulnerability published on August 22, 2026. NLTK before 3.10.3 contains a remote code execution vulnerability in AllowlistUnpickler that validates only the pickle module string and not the global name, allowing attackers to resolve dotted names by attribute traversal to callables outside the allowlisted namespace. Attackers can craft…
When was CVE-2026-71513 disclosed?
CVE-2026-71513 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-71513 actively exploited?
CVE-2026-71513 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 45.2% of all scored CVEs.
What is the CVSS score of CVE-2026-71513?
CVE-2026-71513 has a CVSS v3 base score of 8.8 (NVD).
How do I remediate CVE-2026-71513?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-71513, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-71513

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