wolfSSHd on Windows race condition leading to logon token reused across connections
Summary
| CVE | CVE-2026-83540 |
|---|---|
| State | PUBLISHED |
| Assigner | wolfSSL |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-07 03:16:59 UTC |
| Updated | 2026-10-13 17:33:17 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v4.0 7.7 HIGH from [email protected]
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS: 0.003370000 probability, percentile 0.252800000 (date 2026-10-13)
Problem Types: CWE-287 | CWE-613 | CWE-287 CWE-287 Improper Authentication | CWE-613 CWE-613 Insufficient Session Expiration
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 4.0 | [email protected] | Secondary | 7.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C... |
| 4.0 | CNA | CVSS | 7.7 | HIGH | CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| 3.1 | [email protected] | Primary | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v4.0 Breakdown
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| github.com/wolfSSL/wolfssh/commit/9777bc5ce810d6c418a1473e9e8c40cdb0026e5a | [email protected] | github.com | Patch |
| github.com/wolfSSL/wolfssh/commit/b6bd975ccfac6aadf29b98e35e09114bef3840a9 | [email protected] | github.com | Patch |
| github.com/wolfSSL/wolfssh | [email protected] | github.com | Product |
| www.wolfssl.com/docs/security-vulnerabilities | [email protected] | www.wolfssl.com | Vendor Advisory |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Found by internal wolfSSL testing (en)
Additional Advisory Data
Workarounds
CNA: Restrict which accounts may connect to the affected wolfSSHd instance on Windows hosts until the server is upgraded. Disabling public key authentication alone does not help, because password authentication is affected as well.