CVE-2026-83540

HIGHNVD 8.88.8
EchelonGraph scoreHIGH confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-10-07. NVD baseline CVSS 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week

Also known asEUVD-2026-94163 (ENISA EUVD) · GHSA-36jf-xmwg-5wp8 (GitHub Security Advisories)Source: ENISA EUVD

8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.6%CVSS: 8.8Exploit: 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
8.8
EG Score
8.8HIGHhigh confidence
EG Risk
40
EG Risk 40/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.6%
EPSS %ILE
46th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.6% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 7, 2026

Last Modified

October 13, 2026

Advisory Details (4)

Auto-updated Oct 7, 2026
Patch available. Sources: github_commit.
Web pageMentions a patch (unverified)

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
Web page

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 9× in last 7d / 62× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  4. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  5. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  6. 2026-10-27 21:10 UTCEG score recompute
  7. 2026-10-27 21:10 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH · GitHub CVSS 8.8
  8. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  9. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  10. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  11. 2026-10-25 13:56 UTCEG score recompute
  12. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  13. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  16. 2026-10-20 18:03 UTCEG score recompute
  17. 2026-10-20 18:02 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH · GitHub CVSS 8.8
  18. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  19. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  20. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  21. 2026-10-18 03:07 UTCEG score recompute
  22. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  23. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  24. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
  25. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
Show 37 more
  1. 2026-10-13 17:46 UTCEG score recompute▲ 1.10
  2. 2026-10-13 17:45 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  3. 2026-10-13 17:44 UTCNVD updateCVSS v3 → 8.8
  4. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  5. 2026-10-13 05:44 UTCEG score recompute
  6. 2026-10-13 05:44 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  7. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  8. 2026-10-12 14:54 UTCEG score recompute
  9. 2026-10-11 19:19 UTCEG score recompute
  10. 2026-10-11 17:58 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  11. 2026-10-11 16:35 UTCEG score recompute
  12. 2026-10-11 13:53 UTCEG score recompute
  13. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  14. 2026-10-11 05:45 UTCEG score recompute
  15. 2026-10-11 05:45 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  16. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  17. 2026-10-10 17:35 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  18. 2026-10-10 05:25 UTCEG score recompute
  19. 2026-10-10 05:25 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  20. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  21. 2026-10-09 17:14 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  22. 2026-10-09 04:55 UTCEG score recompute
  23. 2026-10-09 04:55 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  24. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  25. 2026-10-08 16:44 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  26. 2026-10-08 04:26 UTCEG score recompute
  27. 2026-10-08 04:26 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  28. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  29. 2026-10-07 16:15 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  30. 2026-10-07 12:21 UTCEG score recompute
  31. 2026-10-07 12:21 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  32. 2026-10-07 11:38 UTCEG score recompute
  33. 2026-10-07 11:37 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  34. 2026-10-07 03:31 UTCEG score recompute
  35. 2026-10-07 03:31 UTCGHSA enrichmentGHSA-36jf-xmwg-5wp8 · GitHub severity HIGH
  36. 2026-10-07 02:47 UTCEG score recomputeFirst assessed: 7.7 HIGH
  37. 2026-10-07 02:46 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-83540?
CVE-2026-83540 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-83540 published?
The CVE record for CVE-2026-83540 was published on October 7, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 13, 2026; the record at its source may have been updated since.
Is CVE-2026-83540 actively exploited?
CVE-2026-83540 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.6% probability of exploitation in the next 30 days (46th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-83540?
CVE-2026-83540 has a CVSS v3 base score of 8.8 (NVD).
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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