CVE-2026-58491

CRITICALPre-NVD 9.39.3—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 63% of all CVEs by exploit prediction. 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
Trending — 3 sources updated this week
9.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Warpgate is an open source SSH, HTTPS and MySQL bastion host for Linux. Prior to 0.25.5, the /@warpgate/api/sso/providers/:name/start endpoint stores an attacker-controlled next parameter that the POST /@warpgate/api/sso/return handler inserts without HTML escaping into the response generated by warpgate-protocol-http/src/api/sso_provider_list.rs. A victim who follows a crafted link and completes SSO can cause markup and JavaScript to execute in the authenticated Warpgate origin, allowing access to session data and actions through user APIs, and through administrator APIs only when the victim is an administrator. The GET /@warpgate/api/sso/return path also uses the same unvalidated value as a redirect destination, enabling an open redirect. This issue is fixed in version 0.25.5.

CVSS v3
9.3
EG Score
9.3(medium)
EG Risk
42(Track)
EG Risk 42/100SSVC: Track

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
Severity93% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (3)

Auto-updated Sep 23, 2026
🔬 Proof of concept available. Patch available. Sources: github_commit, github_release, github.
github Patch Available🟡 PoC Available

Reflected XSS in SSO return endpoint via attacker-controlled next parameter · Advisory · warp-tech/warpgate · GitHub

https://github.com/warp-tech/warpgate/security/advisories/GHSA-3c3w-75j2-7h74
github_release Patch Available

v0.25.5

Patch available: warp-tech/warpgate v0.25.5

https://github.com/warp-tech/warpgate/releases/tag/v0.25.5
github_commit

commit eab0548f018d (warp-tech/warpgate)

Fix landed in warp-tech/warpgate commit eab0548f018d — awaiting tagged release

https://github.com/warp-tech/warpgate/commit/eab0548f018d95b5f96f8e913527000e05ed93a2

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 8× 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. 2026-09-24 16:39 UTCEG score recompute
  2. 2026-09-24 14:04 UTCEPSS rescore
  3. 2026-09-22 16:22 UTCEG score recompute
  4. 2026-09-22 15:45 UTCEG score recompute
  5. 2026-09-22 15:33 UTCEG score recompute
  6. 2026-09-21 19:28 UTCEG score recompute
  7. 2026-09-21 18:55 UTCEG score recompute
  8. 2026-09-21 18:55 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-58491?
CVE-2026-58491 is a critical vulnerability published on September 21, 2026. Warpgate is an open source SSH, HTTPS and MySQL bastion host for Linux. Prior to 0.25.5, the /@warpgate/api/sso/providers/:name/start endpoint stores an attacker-controlled next parameter that the POST /@warpgate/api/sso/return handler inserts without HTML escaping into the response generated by…
When was CVE-2026-58491 disclosed?
CVE-2026-58491 was first published in the National Vulnerability Database 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-2026-58491 actively exploited?
CVE-2026-58491 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.0% of all scored CVEs.
What is the CVSS score of CVE-2026-58491?
CVE-2026-58491 has a CVSS v3 base score of 9.3 (NVD).
How do I remediate CVE-2026-58491?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-58491, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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