Vulnerability in Warp-Tech Warpgate

CVE-2026-91166

Warpgate is an open source SSH, HTTPS and MySQL bastion host for Linux. From 0.25.0 until 0.27.6, the browser SSH path in warpgate-web-ssh/src/manager.rs handles RCEvent::HostKeyUnknown without the presenting hop identity and instead passes ssh_options.host and ssh_options.port for the final target to KnownHosts::trust. In Prompt and AutoAccept modes, a jump host key can therefore be stored for the target address. A machine later presenting the jump host key at the target address can be accepted as the target, allowing interception of user traffic and a newly issued certificate when certificate authentication is used. The native SSH path is unaffected because it tracks each hop separately. This issue is fixed in version 0.27.6.

CVSS v3 metric

CVSS v3 base score 5.7 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:H/I:H/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-91166?
CVE-2026-91166 is a medium-severity vulnerability in Warp-Tech Warpgate, classified under Improper Validation of Certificate with Host Mismatch. CVSS score: 5.7/10. Published 2026-09-21.
How severe is CVE-2026-91166?
Medium severity. CVSS v3 base score is 5.7 out of 10.