Userauth none bypasses wolfSSHd credential check#940
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padelsbach merged 1 commit intowolfSSL:masterfrom Apr 21, 2026
Merged
Userauth none bypasses wolfSSHd credential check#940padelsbach merged 1 commit intowolfSSL:masterfrom
padelsbach merged 1 commit intowolfSSL:masterfrom
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Pull request overview
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Fixes an authentication bypass in wolfSSHd when built with WOLFSSH_ALLOW_USERAUTH_NONE by preventing USERAUTH_NONE from being treated as an acceptable auth method in the server’s default auth handler.
Changes:
- Reject
WOLFSSH_USERAUTH_NONEinDefaultUserAuth()by removing it from the accepted auth-type allowlist. - Clarify behavior via a comment noting
WOLFSSH_USERAUTH_NONEis not valid for wolfSSHd.
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When wolfsshd is built with WOLFSSH_ALLOW_USERAUTH_NONE, the DefaultUserAuth() function accepted WOLFSSH_USERAUTH_NONE as a valid auth type and forwarded it to RequestAuthentication(). Since RequestAuthentication() only gates credential checks on PASSWORD and PUBLICKEY types, a none request for any existing system user returned success without verifying any credential. Removed USERAUTH_NONE as an accepted auth type in DefaultUserAuth() so it is treated as an invalid auth type for wolfsshd. Affected function: DefaultUserAuth. Issue: F-3215
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padelsbach
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When wolfsshd is built with WOLFSSH_ALLOW_USERAUTH_NONE, the DefaultUserAuth() function accepted WOLFSSH_USERAUTH_NONE as a valid auth type and forwarded it to RequestAuthentication(). Since RequestAuthentication() only gates credential checks on PASSWORD and PUBLICKEY types, a none request for any existing system user returned success without verifying any credential. Removed USERAUTH_NONE as an accepted auth type in DefaultUserAuth() so it is treated as an invalid auth type for wolfsshd.
I want to emphasize, you have to build with the flag WOLFSSH_ALLOW_USERAUTH_NONE for this to be a problem.
Affected function: DefaultUserAuth.
Issue: F-3215