What’s Vulnerable › Vulnerabilities

CVE-2026-83540: wolfSSHd on Windows race condition leading to logon token reused across connections

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-07 · updated 2026-10-13
• Weakness: CWE-287

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.

Affected products

• wolfSSL Inc. wolfSSH: from 1.4.15 before 1.6.0 — fixed in 1.6.0

How to fix

Upgrade to a fixed version: wolfSSL Inc. wolfSSH 1.6.0. Check the vendor advisory for mitigations.

References

• https://github.com/wolfSSL/wolfssh
• https://github.com/wolfSSL/wolfssh/commit/9777bc5ce810d6c418a1473e9e8c40cdb0026e5a
• https://github.com/wolfSSL/wolfssh/commit/b6bd975ccfac6aadf29b98e35e09114bef3840a9
• https://www.wolfssl.com/docs/security-vulnerabilities/

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