CVE-2026-12372

LOWPre-NVD 3.73.7—
EchelonGraph scoreMEDIUM confidence

Score 3.7 from GitHub Security Advisory (severity: LOW) published 2026-08-10. A secondary CVSS source baseline 3.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Elevated
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 3.7Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The nltk.pathsec.validate_network_url() function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space (100.64.0.0/10). This occurs because Python's ipaddress module does not classify such addresses as is_private or is_global, and the current guard only checks is_private and a few explicit categories. An attacker who can influence a URL passed to NLTK's network-loading helpers can exploit this vulnerability to make a strict-mode application send requests to shared-address-space hosts, potentially exposing non-public infrastructure reachable from the application host. The impact is limited to SSRF-style confidentiality exposure, with no code execution claimed.

CVSS v3
3.7
EG Score
3.7LOWmedium confidence
EG Risk
33
EG Risk 33/100CISA SSVC

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
Severity37% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
16th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 9, 2026

Last Modified

September 4, 2026

References (2)

Vendor Advisories for CVE-2026-12372(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 ... 3.9.3-1 (6 versions)
  • every version on: no fix on record
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
nltk0.8 ... 3.9b1 (65 versions)
  • every version up to 3.10.0: fixed in 3.10.0
  • every version through 3.9.4: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 34× 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. 2026-10-10 19:59 UTCEPSS rescore
  2. 2026-10-09 20:06 UTCEPSS rescore
  3. 2026-10-08 17:11 UTCEPSS rescore
  4. 2026-10-07 23:47 UTCEPSS rescore
  5. 2026-10-06 15:17 UTCEPSS rescore
  6. 2026-10-05 17:42 UTCEPSS rescore
  7. 2026-10-04 23:21 UTCEPSS rescore
  8. 2026-10-04 05:38 UTCEG score recompute
  9. 2026-10-03 14:25 UTCEPSS rescore
  10. 2026-10-01 19:49 UTCEPSS rescore
  11. 2026-09-30 22:50 UTCEG score recompute
  12. 2026-09-30 22:50 UTCGHSA enrichment
  13. 2026-09-30 15:02 UTCEPSS rescore
  14. 2026-09-29 15:20 UTCEPSS rescore
  15. 2026-09-28 13:50 UTCEPSS rescore
  16. 2026-09-27 17:02 UTCEG score recompute
  17. 2026-09-27 17:02 UTCGHSA enrichment
  18. 2026-09-26 15:58 UTCEPSS rescore
  19. 2026-09-23 13:47 UTCEPSS rescore
  20. 2026-09-23 02:22 UTCEG score recompute
  21. 2026-09-23 02:22 UTCGHSA enrichment
  22. 2026-09-20 20:15 UTCEPSS rescore
  23. 2026-09-20 01:36 UTCEG score recompute
  24. 2026-09-20 01:36 UTCGHSA enrichment
  25. 2026-09-18 19:27 UTCEPSS rescore
Show 61 more
  1. 2026-09-17 00:51 UTCEG score recompute
  2. 2026-09-17 00:51 UTCGHSA enrichment
  3. 2026-09-16 05:14 UTCEPSS rescore
  4. 2026-09-13 19:13 UTCEG score recompute
  5. 2026-09-13 19:13 UTCGHSA enrichment
  6. 2026-09-13 16:46 UTCEPSS rescore
  7. 2026-09-12 15:00 UTCEPSS rescore
  8. 2026-09-11 14:52 UTCEPSS rescore
  9. 2026-09-11 09:36 UTCEPSS rescore
  10. 2026-09-10 18:20 UTCEG score recompute
  11. 2026-09-10 18:20 UTCGHSA enrichment
  12. 2026-09-10 09:34 UTCEPSS rescore
  13. 2026-09-08 22:00 UTCEPSS rescore
  14. 2026-09-07 17:34 UTCEG score recompute
  15. 2026-09-07 17:34 UTCGHSA enrichment
  16. 2026-09-07 16:01 UTCEPSS rescore
  17. 2026-09-06 13:47 UTCEPSS rescore
  18. 2026-09-04 14:07 UTCEG score recompute
  19. 2026-09-04 14:07 UTCGHSA enrichment
  20. 2026-09-04 05:06 UTCEPSS rescore
  21. 2026-09-03 20:32 UTCEG score recompute
  22. 2026-09-03 20:32 UTCGHSA enrichment
  23. 2026-09-02 14:11 UTCEPSS rescore
  24. 2026-09-01 13:53 UTCEPSS rescore
  25. 2026-09-01 04:39 UTCEPSS rescore
  26. 2026-08-31 19:41 UTCGHSA enrichment
  27. 2026-08-30 23:08 UTCEG score recompute
  28. 2026-08-30 23:08 UTCGHSA enrichment
  29. 2026-08-30 19:17 UTCEPSS rescore
  30. 2026-08-30 01:21 UTCEPSS rescore
  31. 2026-08-28 21:40 UTCEPSS rescore
  32. 2026-08-27 22:23 UTCEG score recompute
  33. 2026-08-27 22:23 UTCGHSA enrichment
  34. 2026-08-25 13:48 UTCEPSS rescore
  35. 2026-08-24 21:38 UTCEG score recompute
  36. 2026-08-24 21:38 UTCGHSA enrichment
  37. 2026-08-23 00:19 UTCEPSS rescore
  38. 2026-08-21 23:48 UTCEPSS rescore
  39. 2026-08-21 20:34 UTCEG score recompute
  40. 2026-08-21 20:34 UTCGHSA enrichment
  41. 2026-08-20 22:55 UTCEPSS rescore
  42. 2026-08-19 17:03 UTCEPSS rescore
  43. 2026-08-18 19:48 UTCEG score recompute
  44. 2026-08-18 19:48 UTCGHSA enrichment
  45. 2026-08-18 13:48 UTCEPSS rescore
  46. 2026-08-16 14:56 UTCEPSS rescore
  47. 2026-08-16 02:14 UTCEPSS rescore
  48. 2026-08-15 19:04 UTCEG score recompute
  49. 2026-08-15 19:04 UTCGHSA enrichment
  50. 2026-08-15 01:30 UTCEPSS rescore
  51. 2026-08-13 22:00 UTCEPSS rescore
  52. 2026-08-12 18:19 UTCEG score recompute
  53. 2026-08-12 18:19 UTCGHSA enrichment
  54. 2026-08-12 17:51 UTCEG score recompute
  55. 2026-08-12 17:51 UTCGHSA enrichment
  56. 2026-08-12 13:50 UTCEPSS rescore
  57. 2026-08-11 13:42 UTCEPSS rescore
  58. 2026-08-10 23:59 UTCEPSS rescore
  59. 2026-08-09 23:19 UTCEG score recompute
  60. 2026-08-09 22:56 UTCEG score recompute
  61. 2026-08-09 22:56 UTCMITRE cvelistV5first tracked

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-12372?
CVE-2026-12372 is a low vulnerability published on August 9, 2026. A Server-Side Request Forgery (SSRF) vulnerability exists in nltk/nltk versions 3.9.4 and the current develop branch. The nltk.pathsec.validatenetworkurl() function, intended to prevent SSRF by rejecting internal network addresses, fails to reject IPs in the RFC 6598 shared address space…
When was CVE-2026-12372 disclosed?
CVE-2026-12372 was first published on August 9, 2026, with the most recent update on September 4, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-12372 actively exploited?
CVE-2026-12372 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (16th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-12372?
CVE-2026-12372 has a CVSS base score of 3.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-12372?
A fix for CVE-2026-12372 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-12372 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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