CVE-2026-83540

HIGHPre-NVD 7.77.7—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (25th percentile of EPSS-scored CVEs). 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 — 4 sources updated this week
7.7EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 7.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

When password or public key authentication is used with the Windows port of wolfSSHd, the Windows logon token acquired for one authenticated connection is not released before a token is acquired for a subsequent connection, resulting in user login poisoning between connections. A less privileged user with a valid account on the server can exploit this to force a login as a more privileged user. The vulnerability was introduced with the initial Windows port of wolfSSHd in wolfSSH version 1.4.15 and affects all versions through 1.5.0. Non-Windows builds of wolfSSHd are not affected.

CVSS v3
7.7
EG Score
7.7HIGHmedium confidence
EG Risk
35
EG Risk 35/100CISA 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
Severity77% × 45%
Exploitation0% × 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
25th
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 none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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

October 7, 2026

Last Modified

October 7, 2026

Advisory Details (4)

Auto-updated Oct 7, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit.
genericMentions a patch (unverified)🟡 PoC Available

wolfSSL Security Vulnerabilities | Documentation - wolfSSL

https://www.wolfssl.com/docs/security-vulnerabilities/
github_commit Patch Available

commit 9777bc5ce810 (wolfSSL/wolfssh)

Patch available: wolfSSL/wolfssh v1.6.0-stable (contains commit 9777bc5ce810)

https://github.com/wolfSSL/wolfssh/commit/9777bc5ce810d6c418a1473e9e8c40cdb0026e5a
github_commit Patch Available

commit b6bd975ccfac (wolfSSL/wolfssh)

Patch available: wolfSSL/wolfssh v1.6.0-stable (contains commit b6bd975ccfac)

https://github.com/wolfSSL/wolfssh/commit/b6bd975ccfac6aadf29b98e35e09114bef3840a9
generic

GitHub - wolfSSL/wolfssh: wolfSSH is a small, fast, portable SSH implementation, including support for SCP and SFTP. · GitHub

https://github.com/wolfSSL/wolfssh

Vendor Advisories for CVE-2026-83540(1)

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

Weakness Classification(2)

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

Data Freshness Timeline

(refreshed 18× in last 7d / 18× 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. 2026-10-09 20:07 UTCEPSS rescore
  2. 2026-10-09 17:14 UTCGHSA enrichment
  3. 2026-10-09 04:55 UTCEG score recompute
  4. 2026-10-09 04:55 UTCGHSA enrichment
  5. 2026-10-08 17:13 UTCEPSS rescore
  6. 2026-10-08 16:44 UTCGHSA enrichment
  7. 2026-10-08 04:26 UTCEG score recompute
  8. 2026-10-08 04:26 UTCGHSA enrichment
  9. 2026-10-07 23:48 UTCEPSS rescore
  10. 2026-10-07 16:15 UTCGHSA enrichment
  11. 2026-10-07 12:21 UTCEG score recompute
  12. 2026-10-07 12:21 UTCGHSA enrichment
  13. 2026-10-07 11:38 UTCEG score recompute
  14. 2026-10-07 11:37 UTCGHSA enrichment
  15. 2026-10-07 03:31 UTCEG score recompute
  16. 2026-10-07 03:31 UTCGHSA enrichment
  17. 2026-10-07 02:47 UTCEG score recompute
  18. 2026-10-07 02:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-83540?
CVE-2026-83540 is a high vulnerability published on October 7, 2026. When password or public key authentication is used with the Windows port of wolfSSHd, the Windows logon token acquired for one authenticated connection is not released before a token is acquired for a subsequent connection, resulting in user login poisoning between connections. A less privileged…
When was CVE-2026-83540 disclosed?
CVE-2026-83540 was first published on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-83540 actively exploited?
CVE-2026-83540 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-83540?
CVE-2026-83540 has a CVSS base score of 7.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-83540?
A fix for CVE-2026-83540 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-83540 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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