User-controlled Duo host permits authenticated SSRF in Psono Server

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

Psono Server CE && EE versions 0.1.0 through 7.2.3 accepted a user-controlled host when configuring a personal Duo device and passed it to the Duo client without an allowlist or explicit timeout. An authenticated remote attacker could cause the server to connect to selected hosts over HTTPS on port 443 and distinguish failure modes, providing an internal DNS and service-reachability oracle. Connections still required TLS certificate validation, and the flaw did not provide arbitrary protocol or port access. Unresponsive targets could also occupy a server worker until the operating-system timeout.

Source published

27 Oct 2026 05:55:07 UTC

Source modified

27 Oct 2026 05:55:07 UTC

Observed here

27 Oct 2026 07:22:55 UTC

Source terms

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CVSS 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L