High severity · published Oct 7, 2026
CVE-2026-83540
wolfSSHd on Windows race condition leading to logon token reused across connections
8.8
CVSS
0.6%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 46% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WO
wolfSSH · wolfSSL
1.4.15 through 1.5.0 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-83540
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-83540
product
https://github.com/wolfSSL/wolfssh
patch
https://github.com/wolfSSL/wolfssh/commit/b6bd975ccfac6aadf29b98e35e09114bef3840a9
patch
https://github.com/wolfSSL/wolfssh/commit/9777bc5ce810d6c418a1473e9e8c40cdb0026e5a
vendor-advisory
https://www.wolfssl.com/docs/security-vulnerabilities/
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