CVE-2026-63310

HIGHPre-NVD 7.17.1—
EchelonGraph scoreHIGH confidence

Score 7.1 from GitHub Security Advisory (severity: CRITICAL) published 2026-08-22. a secondary CVSS source baseline 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.1Exploit: Elevated riskExposed: 0

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

NLTK before 3.9.3 fails to verify file integrity after downloading packages and before extraction in the downloader module. Attackers can perform man-in-the-middle attacks or DNS poisoning to inject malicious package contents that are extracted without validation.

CVSS v3
7.1
EG Score
7.1(high)
EG Risk
48(Track*)
EG Risk 48/100SSVC: 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
Severity71% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Watch closely — could escalate to Attend.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

August 22, 2026

Last Modified

August 28, 2026

Advisory Details (2)

Auto-updated Aug 22, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

NLTK before 3.9.3 Missing Post-Download Integrity Verification | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nltk-before-missing-post-download-integrity-verification
github Patch Available🟡 PoC Available

Missing Post-Download Integrity Verification Allows Malicious Package Injection · Advisory · nltk/nltk · GitHub

https://github.com/nltk/nltk/security/advisories/GHSA-5wp5-5229-5g6q

Vendor Advisories for CVE-2026-63310(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 30× in last 7d / 35× 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. 2026-08-30 04:55 UTCEG score recompute
  2. 2026-08-30 04:55 UTCGHSA enrichment
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-29 17:41 UTCGHSA enrichment
  5. 2026-08-29 06:24 UTCEG score recompute
  6. 2026-08-29 06:24 UTCGHSA enrichment
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 19:09 UTCGHSA enrichment
  9. 2026-08-28 14:55 UTCGHSA enrichment
  10. 2026-08-28 03:39 UTCGHSA enrichment
  11. 2026-08-27 16:25 UTCEG score recompute
  12. 2026-08-27 16:25 UTCGHSA enrichment
  13. 2026-08-27 14:25 UTCEPSS rescore
  14. 2026-08-27 05:06 UTCGHSA enrichment
  15. 2026-08-26 17:51 UTCEG score recompute
  16. 2026-08-26 17:51 UTCGHSA enrichment
  17. 2026-08-26 14:46 UTCEPSS rescore
  18. 2026-08-26 06:10 UTCGHSA enrichment
  19. 2026-08-25 18:55 UTCEG score recompute
  20. 2026-08-25 18:55 UTCGHSA enrichment
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-25 07:41 UTCGHSA enrichment
  23. 2026-08-24 20:27 UTCEG score recompute
  24. 2026-08-24 20:26 UTCGHSA enrichment
  25. 2026-08-24 19:22 UTCEG score recompute
Show 10 more
  1. 2026-08-24 19:22 UTCGHSA enrichment
  2. 2026-08-24 12:28 UTCEG score recompute
  3. 2026-08-24 12:28 UTCGHSA enrichment
  4. 2026-08-24 01:07 UTCGHSA enrichment
  5. 2026-08-23 13:53 UTCGHSA enrichment
  6. 2026-08-23 02:38 UTCEG score recompute
  7. 2026-08-23 02:38 UTCGHSA enrichment
  8. 2026-08-22 15:24 UTCEG score recompute
  9. 2026-08-22 14:26 UTCEG score recompute
  10. 2026-08-22 14:25 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-63310?
CVE-2026-63310 is a high vulnerability published on August 22, 2026. NLTK before 3.9.3 fails to verify file integrity after downloading packages and before extraction in the downloader module. Attackers can perform man-in-the-middle attacks or DNS poisoning to inject malicious package contents that are extracted without validation.
When was CVE-2026-63310 disclosed?
CVE-2026-63310 was first published in the National Vulnerability Database on August 22, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-63310 actively exploited?
CVE-2026-63310 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 98.6% of all scored CVEs.
What is the CVSS score of CVE-2026-63310?
CVE-2026-63310 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2026-63310?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63310, 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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