CVE-2026-58491

CRITICALPre-NVD 9.39.3
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This critical-severity CVE scores 9.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (39th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-84059 (ENISA EUVD)Source: ENISA EUVD

9.3EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 9.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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
9.3CRITICALmedium confidence
EG Risk
42
EG Risk 42/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity93% × 45%
Impact severity (EG Severity): CVSS 9.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.5%
EPSS %ILE
39th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.3): severity, escalated by confirmed exploitation. This CVE's 9.3 is its impact severity (EG Severity), not escalated.

EG Severity
9.3 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 21, 2026

Last Modified

September 24, 2026

Advisory Details (3)

Auto-updated Oct 3, 2026
Patch available. Sources: github_release, github, github_commit.
GitHub advisoryMentions a patch (unverified)

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 14× in last 7d / 64× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-11-01 19:03 UTCEG score recompute
  2. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  3. 2026-10-31 20:15 UTCEG score recompute
  4. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  5. 2026-10-30 21:29 UTCEG score recompute
  6. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  7. 2026-10-29 22:41 UTCEG score recompute
  8. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  9. 2026-10-28 23:55 UTCEG score recompute
  10. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  11. 2026-10-28 01:07 UTCEG score recompute
  12. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  13. 2026-10-27 02:17 UTCEG score recompute
  14. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  15. 2026-10-25 23:26 UTCEG score recompute
  16. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  17. 2026-10-25 14:16 UTCEG score recompute
  18. 2026-10-25 00:37 UTCEG score recompute
  19. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  20. 2026-10-24 01:51 UTCEG score recompute
  21. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  22. 2026-10-23 03:03 UTCEG score recompute
  23. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  24. 2026-10-22 04:14 UTCEG score recompute
  25. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
Show 63 more
  1. 2026-10-21 05:22 UTCEG score recompute
  2. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  3. 2026-10-20 06:34 UTCEG score recompute
  4. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  5. 2026-10-19 07:44 UTCEG score recompute
  6. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  7. 2026-10-18 03:27 UTCEG score recompute
  8. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  9. 2026-10-17 06:12 UTCEG score recompute
  10. 2026-10-16 16:43 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  11. 2026-10-16 07:20 UTCEG score recompute
  12. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  13. 2026-10-15 06:14 UTCEG score recompute
  14. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  15. 2026-10-14 01:52 UTCEG score recompute
  16. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  17. 2026-10-12 22:07 UTCEG score recompute
  18. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  19. 2026-10-12 15:53 UTCEG score recompute
  20. 2026-10-11 19:36 UTCEG score recompute
  21. 2026-10-11 16:51 UTCEG score recompute
  22. 2026-10-11 14:14 UTCEG score recompute
  23. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  24. 2026-10-10 22:37 UTCEG score recompute
  25. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  26. 2026-10-09 22:06 UTCEG score recompute
  27. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  28. 2026-10-08 17:19 UTCEG score recompute
  29. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  30. 2026-10-08 02:57 UTCEG score recompute
  31. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  32. 2026-10-06 18:44 UTCEG score recompute
  33. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  34. 2026-10-05 18:15 UTCEG score recompute
  35. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  36. 2026-10-05 02:07 UTCEG score recompute
  37. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  38. 2026-10-03 17:42 UTCEG score recompute
  39. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  40. 2026-10-02 21:29 UTCEG score recompute
  41. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  42. 2026-10-01 21:03 UTCEG score recompute
  43. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  44. 2026-09-30 16:48 UTCEG score recompute
  45. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  46. 2026-09-29 19:15 UTCEG score recompute
  47. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  48. 2026-09-28 23:00 UTCEG score recompute
  49. 2026-09-28 14:57 UTCEG score recompute
  50. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  51. 2026-09-27 14:49 UTCEG score recompute
  52. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  53. 2026-09-26 18:42 UTCEG score recompute
  54. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  55. 2026-09-26 02:28 UTCEG score recompute
  56. 2026-09-24 16:39 UTCEG score recompute
  57. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  58. 2026-09-22 16:22 UTCEG score recompute
  59. 2026-09-22 15:45 UTCEG score recompute
  60. 2026-09-22 15:33 UTCEG score recompute
  61. 2026-09-21 19:28 UTCEG score recompute
  62. 2026-09-21 18:55 UTCEG score recomputeFirst assessed: 9.3 CRITICAL
  63. 2026-09-21 18:55 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-58491?
CVE-2026-58491 is a critical-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-58491 published?
The CVE record for CVE-2026-58491 was published on September 21, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 24, 2026; the record at its source may have been updated since.
Is CVE-2026-58491 actively exploited?
CVE-2026-58491 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (39th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-58491?
CVE-2026-58491 has a CVSS base score of 9.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-58491?
A fix for CVE-2026-58491 is available: update to the fixed version the vendor names in its advisory.

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