CVE-2026-78221

MEDIUMPre-NVD 5.95.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1%, top 98% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
5.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.9Exploit: None knownExposed: 0

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

An incorrect buffer size calculation in the Windows Interactive Service in OpenVPN 2.7_alpha1 through 2.7.6 allows local authenticated users to cause memory corruption or disclose sensitive information via crafted NRPT inputs.

CVSS v3
5.9
EG Score
5.9(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: 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
Severity59% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
2%
KEV
Not listed

Published

September 7, 2026

Last Modified

September 8, 2026

References (1)

Vendor Advisories for CVE-2026-78221(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 17× in last 7d / 37× 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. 2026-09-18 19:55 UTCEG score recompute
  2. 2026-09-18 19:55 UTCGHSA enrichment
  3. 2026-09-18 19:28 UTCEPSS rescore
  4. 2026-09-17 20:21 UTCEG score recompute
  5. 2026-09-17 20:21 UTCGHSA enrichment
  6. 2026-09-16 18:20 UTCEG score recompute
  7. 2026-09-16 18:20 UTCGHSA enrichment
  8. 2026-09-16 14:08 UTCEPSS rescore
  9. 2026-09-16 05:15 UTCEPSS rescore
  10. 2026-09-15 16:52 UTCEG score recompute
  11. 2026-09-15 16:52 UTCGHSA enrichment
  12. 2026-09-15 03:12 UTCEPSS rescore
  13. 2026-09-15 03:12 UTCEPSS rescore
  14. 2026-09-14 17:18 UTCGHSA enrichment
  15. 2026-09-13 17:44 UTCEG score recompute
  16. 2026-09-13 17:44 UTCGHSA enrichment
  17. 2026-09-12 18:10 UTCGHSA enrichment
  18. 2026-09-11 18:36 UTCEG score recompute
  19. 2026-09-11 18:36 UTCGHSA enrichment
  20. 2026-09-11 14:53 UTCEPSS rescore
  21. 2026-09-11 14:53 UTCEPSS rescore
  22. 2026-09-10 19:02 UTCEG score recompute
  23. 2026-09-10 19:01 UTCGHSA enrichment
  24. 2026-09-10 09:35 UTCEPSS rescore
  25. 2026-09-09 19:27 UTCEG score recompute
Show 12 more
  1. 2026-09-09 19:27 UTCGHSA enrichment
  2. 2026-09-08 22:01 UTCEPSS rescore
  3. 2026-09-08 19:53 UTCGHSA enrichment
  4. 2026-09-08 16:03 UTCEG score recompute
  5. 2026-09-08 16:02 UTCGHSA enrichment
  6. 2026-09-08 15:04 UTCEG score recompute
  7. 2026-09-08 15:03 UTCGHSA enrichment
  8. 2026-09-08 08:02 UTCEG score recompute
  9. 2026-09-08 08:02 UTCGHSA enrichment
  10. 2026-09-07 08:29 UTCEG score recompute
  11. 2026-09-07 07:39 UTCEG score recompute
  12. 2026-09-07 07:36 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-78221?
CVE-2026-78221 is a medium vulnerability published on September 7, 2026. An incorrect buffer size calculation in the Windows Interactive Service in OpenVPN 2.7_alpha1 through 2.7.6 allows local authenticated users to cause memory corruption or disclose sensitive information via crafted NRPT inputs.
When was CVE-2026-78221 disclosed?
CVE-2026-78221 was first published in the National Vulnerability Database on September 7, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-78221 actively exploited?
CVE-2026-78221 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 98.2% of all scored CVEs.
What is the CVSS score of CVE-2026-78221?
CVE-2026-78221 has a CVSS v3 base score of 5.9 (NVD).
How do I remediate CVE-2026-78221?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-78221, 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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