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Vulnerability · Published Oct 27, 2026 · Assigned by esaqa

CVE-2026-117470WebAuthn assertion replay permits second-factor bypass in Psono Server

Medium 6.5

In plain English

A medium-severity security flaw in Psono from esaqa GmbH. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities).

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.4%top 64.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
esaqa GmbH Psono 3.1.0 – before 7.2.4

Weakness: CWE-294 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:N

References