Psono Server CE & EE versions 3.1.0 through 7.2.3 did not consume a stored WebAuthn challenge after assertion verification. An unauthenticated remote attacker who possessed the user's password and one captured valid WebAuthn assertion could replay that assertion with separate login tokens while the stored challenge remained unchanged, bypassing the WebAuthn second factor. The attack required capture of a valid assertion and did not itself disclose plaintext secrets.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
High
Complete data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
Vulnerable Products
esaqa gmbh:psono
References 5
https://gitlab.com/esaqa/esaqa/security-advisories/-/blob/master/advisories/CVE…
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https://gitlab.com/esaqa/psono/psono-server
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https://gitlab.com/esaqa/psono/psono-server/-/blob/v7.2.3/psono/restapi/seriali…
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https://gitlab.com/esaqa/psono/psono-server/-/commit/9c9a7f1701535df63370340dcc…
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https://gitlab.com/esaqa/psono/psono-server/-/releases/v7.2.4
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