CVE-2026-91166

MEDIUMPre-NVD 5.75.7—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.7 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (11th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
5.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.7Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

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
5.7
EG Score
5.7MEDIUMmedium confidence
EG Risk
42
EG Risk 42/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity57% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low, Track* at medium and Attend at high mission impact.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.2%
EPSS %ILE
11th
KEV
Not listed

CISA SSVCTrack at low, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (3)

Auto-updated Sep 21, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
github_release Patch Available

v0.27.6

Patch available: warp-tech/warpgate v0.27.6

https://github.com/warp-tech/warpgate/releases/tag/v0.27.6
github_commit

commit fb66ff74f979 (warp-tech/warpgate)

Fix landed in warp-tech/warpgate commit fb66ff74f979 — awaiting tagged release

https://github.com/warp-tech/warpgate/commit/fb66ff74f979c22054f4d348cc0d9065cc67e5d3
github Patch Available🟡 PoC Available

WebSSH client stores a duplicate of jump host's key for the target's address · Advisory · warp-tech/warpgate · GitHub

https://github.com/warp-tech/warpgate/security/advisories/GHSA-w9jj-vpw3-5r8f

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 23× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-03 13:52 UTCEG score recompute
  2. 2026-10-02 14:56 UTCEG score recompute
  3. 2026-10-01 19:51 UTCEPSS rescore
  4. 2026-09-30 17:11 UTCEG score recompute
  5. 2026-09-30 15:04 UTCEPSS rescore
  6. 2026-09-29 18:18 UTCEG score recompute
  7. 2026-09-28 19:15 UTCEG score recompute
  8. 2026-09-28 13:52 UTCEPSS rescore
  9. 2026-09-28 13:52 UTCEPSS rescore
  10. 2026-09-27 20:17 UTCEG score recompute
  11. 2026-09-27 13:49 UTCEPSS rescore
  12. 2026-09-26 21:25 UTCEG score recompute
  13. 2026-09-26 15:59 UTCEPSS rescore
  14. 2026-09-24 23:38 UTCEG score recompute
  15. 2026-09-24 22:42 UTCEG score recompute
  16. 2026-09-24 16:06 UTCEG score recompute
  17. 2026-09-24 14:04 UTCEPSS rescore
  18. 2026-09-23 17:54 UTCEPSS rescore
  19. 2026-09-22 18:21 UTCEG score recompute
  20. 2026-09-22 16:01 UTCEPSS rescore
  21. 2026-09-21 19:28 UTCEG score recompute
  22. 2026-09-21 19:00 UTCEG score recompute
  23. 2026-09-21 19:00 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-91166?
CVE-2026-91166 is a medium vulnerability published on September 21, 2026. 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 sshoptions.host and sshoptions.port for the final target…
When was CVE-2026-91166 disclosed?
CVE-2026-91166 was first published on September 21, 2026, with the most recent update on September 24, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91166 actively exploited?
CVE-2026-91166 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (11th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91166?
CVE-2026-91166 has a CVSS base score of 5.7 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-91166?
A fix for CVE-2026-91166 is available: update to the fixed version the vendor names in its advisory.

Dependency Blast Radius

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