CVE-2026-63312

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-22. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 3 sources updated this weekElevated
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: Elevated riskExposed: 0

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

NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can read arbitrary local files regardless of the ENFORCE setting, including sensitive system files and application credentials.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
65(Attend)
EG Risk 65/100SSVC: Attend

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%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
40%
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 StreamBackedCorpusView Bypasses pathsec.ENFORCE Arbitrary File Read | Advisories | VulnCheck

https://www.vulncheck.com/advisories/nltk-streambackedcorpusview-bypasses-pathsec-enforce-arbitrary-file-read
github Patch Available🟡 PoC Available

Security Report: StreamBackedCorpusView Bypasses pathsec.ENFORCE - Arbitrary Local File Read · Advisory · nltk/nltk · GitHub

https://github.com/nltk/nltk/security/advisories/GHSA-x5ph-mj9p-rfr8

Vendor Advisories for CVE-2026-63312(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 05:30 UTCEG score recompute
  2. 2026-08-30 05:30 UTCGHSA enrichment
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-29 18:04 UTCGHSA enrichment
  5. 2026-08-29 06:38 UTCEG score recompute
  6. 2026-08-29 06:38 UTCGHSA enrichment
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 19:09 UTCGHSA enrichment
  9. 2026-08-28 18:03 UTCGHSA enrichment
  10. 2026-08-28 05:45 UTCGHSA enrichment
  11. 2026-08-27 18:18 UTCEG score recompute
  12. 2026-08-27 18:18 UTCGHSA enrichment
  13. 2026-08-27 14:25 UTCEPSS rescore
  14. 2026-08-27 05:19 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 05:41 UTCGHSA enrichment
  19. 2026-08-25 18:16 UTCEG score recompute
  20. 2026-08-25 18:16 UTCGHSA enrichment
  21. 2026-08-25 13:49 UTCEPSS rescore
  22. 2026-08-25 06:51 UTCGHSA enrichment
  23. 2026-08-24 19:26 UTCEG score recompute
  24. 2026-08-24 19:26 UTCGHSA enrichment
  25. 2026-08-24 18:51 UTCEG score recompute
Show 10 more
  1. 2026-08-24 18:51 UTCGHSA enrichment
  2. 2026-08-24 13:06 UTCEG score recompute
  3. 2026-08-24 13:06 UTCGHSA enrichment
  4. 2026-08-24 01:40 UTCGHSA enrichment
  5. 2026-08-23 14:15 UTCGHSA enrichment
  6. 2026-08-23 02:49 UTCEG score recompute
  7. 2026-08-23 02:49 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

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-63312?
CVE-2026-63312 is a high vulnerability published on August 22, 2026. NLTK before 3.10.0 contains an arbitrary local file read vulnerability in StreamBackedCorpusView that bypasses pathsec.ENFORCE by calling builtins.open() directly instead of pathsec.open(). Attackers who control the fileid argument can read arbitrary local files regardless of the ENFORCE setting,…
When was CVE-2026-63312 disclosed?
CVE-2026-63312 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-2026-63312 actively exploited?
CVE-2026-63312 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 60.1% of all scored CVEs.
What is the CVSS score of CVE-2026-63312?
CVE-2026-63312 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-63312?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-63312, 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

Explore the affected products and dependency analysis for CVE-2026-63312

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