CVE-2026-71513

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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, GitHub Security Advisory, a secondary CVSS source
8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1.1%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
8.8HIGHmedium confidence
EG Risk
40
EG Risk 40/100

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 (value × EchelonGraph’s weight)
Severity88% × 45%
The EG Score, 8.8 of 10.
Exploitation1.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
1.1%
EPSS %ILE
64th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 22, 2026

Last Modified

September 16, 2026

Advisory Details (4)

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

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
Web page

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
Web page

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 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
nltk3.10.0-1, 3.10.1-1, 3.9.1-2, 3.9.2-1, 3.9.3-1
  • every version up to 3.10.3-1: fixed in 3.10.3-1
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
nltk3.10.0, 3.10.1, 3.10.2
  • 3.10.0 up to 3.10.3: fixed in 3.10.3
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 15× in last 7d / 53× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 122 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 22 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:35 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  2. 2026-10-13 08:27 UTCEG score recompute
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  4. 2026-10-12 15:42 UTCEG score recompute
  5. 2026-10-11 19:28 UTCEG score recompute
  6. 2026-10-11 16:43 UTCEG score recompute
  7. 2026-10-11 14:03 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  10. 2026-10-10 16:37 UTCEG score recompute
  11. 2026-10-09 20:07 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  12. 2026-10-09 05:34 UTCEG score recompute
  13. 2026-10-08 17:13 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  14. 2026-10-08 04:44 UTCEG score recompute
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  16. 2026-10-06 19:23 UTCEG score recompute
  17. 2026-10-06 15:18 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  18. 2026-10-06 07:48 UTCEG score recompute
  19. 2026-10-05 17:43 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  20. 2026-10-05 04:53 UTCEG score recompute
  21. 2026-10-04 23:22 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  22. 2026-10-03 16:39 UTCEG score recompute
  23. 2026-10-03 14:26 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  24. 2026-10-02 20:58 UTCEG score recompute
  25. 2026-10-01 21:23 UTCEG score recompute
Show 75 more
  1. 2026-10-01 19:50 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  2. 2026-09-30 20:22 UTCEG score recompute
  3. 2026-09-30 15:03 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  4. 2026-09-29 15:34 UTCEG score recompute
  5. 2026-09-28 23:32 UTCEG score recompute
  6. 2026-09-28 13:52 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  7. 2026-09-28 00:21 UTCEG score recompute
  8. 2026-09-27 13:48 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  9. 2026-09-27 01:08 UTCEG score recompute
  10. 2026-09-26 15:59 UTCEPSS rescoreEPSS 1.1% · 64th percentile
  11. 2026-09-24 19:18 UTCEG score recompute
  12. 2026-09-23 20:07 UTCEG score recompute
  13. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  14. 2026-09-22 20:56 UTCEG score recompute
  15. 2026-09-21 21:42 UTCEG score recompute
  16. 2026-09-21 21:09 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  17. 2026-09-20 22:32 UTCEG score recompute
  18. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  19. 2026-09-19 23:21 UTCEG score recompute
  20. 2026-09-19 00:03 UTCEG score recompute
  21. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  22. 2026-09-18 00:45 UTCEG score recompute
  23. 2026-09-17 01:13 UTCEG score recompute
  24. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  25. 2026-09-16 09:34 UTCEG score recompute
  26. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  27. 2026-09-15 09:49 UTCEG score recompute
  28. 2026-09-15 03:12 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  29. 2026-09-13 22:55 UTCEG score recompute
  30. 2026-09-12 23:45 UTCEG score recompute
  31. 2026-09-12 15:02 UTCEPSS rescoreEPSS 0.8% · 54th percentile
  32. 2026-09-12 00:34 UTCEG score recompute
  33. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  34. 2026-09-11 12:58 UTCEG score recompute
  35. 2026-09-10 13:26 UTCEG score recompute
  36. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  37. 2026-09-09 01:42 UTCEG score recompute
  38. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  39. 2026-09-07 17:04 UTCEG score recompute
  40. 2026-09-06 17:53 UTCEG score recompute
  41. 2026-09-06 13:48 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  42. 2026-09-05 18:41 UTCEG score recompute
  43. 2026-09-04 19:30 UTCEG score recompute
  44. 2026-09-04 07:49 UTCEG score recompute
  45. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  46. 2026-09-02 20:55 UTCEG score recompute
  47. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  48. 2026-09-02 07:46 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  49. 2026-09-01 20:11 UTCEG score recompute
  50. 2026-09-01 20:11 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  51. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  52. 2026-09-01 08:35 UTCEG score recompute
  53. 2026-09-01 08:35 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  54. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  55. 2026-08-31 20:56 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  56. 2026-08-31 17:55 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  57. 2026-08-31 04:22 UTCEG score recompute
  58. 2026-08-31 04:22 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  59. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  60. 2026-08-30 16:47 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  61. 2026-08-30 05:12 UTCEG score recompute
  62. 2026-08-30 05:12 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  63. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  64. 2026-08-29 17:36 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  65. 2026-08-29 05:41 UTCEG score recompute
  66. 2026-08-29 05:40 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  67. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.8% · 53rd percentile
  68. 2026-08-28 18:05 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  69. 2026-08-28 05:16 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  70. 2026-08-27 17:37 UTCEG score recompute
  71. 2026-08-27 17:37 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  72. 2026-08-27 17:17 UTCEG score recompute
  73. 2026-08-27 17:17 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  74. 2026-08-27 14:22 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8
  75. 2026-08-27 02:46 UTCGHSA enrichmentGHSA-5gh2-94qg-qppq · GitHub severity HIGH · GitHub CVSS 8.8

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-71513?
CVE-2026-71513 is a high-severity vulnerability; its CVE record was 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 made public?
CVE-2026-71513 was made public on August 11, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on August 22, 2026. EchelonGraph's copy of the record carries a last-modified date of September 16, 2026; the record at its source may have been updated since.
Is CVE-2026-71513 actively exploited?
CVE-2026-71513 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.1% probability of exploitation in the next 30 days (64th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-71513?
CVE-2026-71513 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-71513?
A fix for CVE-2026-71513 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-71513 are linked in the Vendor Advisories panel on this page.

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