CVE-2026-58491

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: CRITICAL
CVSS score: 9.3 / 10
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Effective score: 9.3 / 10 CRITICAL source: CNA overview
CWE(s): CWE-79
Reserved: 2026-06-30
Published: 2026-09-21 18:48 UTC
Last updated: 2026-09-21 18:48 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/58xxx/CVE-2026-58491.json
Linked Threat: CVE-2026-58491 — Warpgate: Reflected XSS in SSO return endpoint via attacker-controlled next parameter

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-21 19:17:06 UTC
NVD last modified: 2026-09-21 19:17:06 UTC
NVD CVSS v3.1: 9.3 / 10 CRITICAL source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
Exploitability subscore: 2.8 / 10
Impact subscore: 5.8 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84059
Assigner: GitHub_M
Published: Sep 21, 2026, 6:48:03 PM
Updated: Sep 21, 2026, 6:48:03 PM
EUVD base score (CVSS 3.1): 9.3 / 10
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N
EUVD-reported EPSS: 0.0000
Vendors: warp-tech
Products: warpgate (< 0.25.5)

ENISA description: 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.

EUVD references (3)

Affected products (1)

Vendor	Product	Versions	Platforms
warp-tech	warpgate	`< 0.25.5` (affected)	—

Vendor references (3)

References embedded in the original CVE record by the assigning CNA.

https://github.com/warp-tech/warpgate/security/advisories/GHSA-3c3w-75j2-7h74 x_refsource_CONFIRM
https://github.com/warp-tech/warpgate/commit/eab0548f018d95b5f96f8e913527000e05ed93a2 x_refsource_MISC
https://github.com/warp-tech/warpgate/releases/tag/v0.25.5 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (3)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/warp-tech/warpgate/commit/eab0548f018d95b5f96f8e913527000e05ed93a2 security-advisories@github.com
https://github.com/warp-tech/warpgate/releases/tag/v0.25.5 security-advisories@github.com
https://github.com/warp-tech/warpgate/security/advisories/GHSA-3c3w-75j2-7h74 security-advisories@github.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-58491: warpgate Critical Vulnerability — Advisory | IT ...

web:itknowledgebases.com

Export to CSV for reporting, ticketing, or patch prioritization workflows. What Is a CVE Advisory? A CVE (Common Vulnerabilities and Exposures) advisory is a public disclosure of a security vulnerability assigned a unique identifier by MITRE. Advisories include severity scores (CVSS), affected versions, and remediation guidance.

2026-09-22 16:47 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-22 16:47 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-09-22 16:47 UTC
Google fixes the seventh actively exploited Chrome zero-day of 2026

web:securityaffairs.com

Google patched 230 Chrome flaws, including an actively exploited V8 bug that could let attackers run arbitrary code through a crafted HTML page. Google released a Chrome update fixing 230 security vulnerabilities, including one already exploited in the wild tracked as CVE - 2026 -87491 (CVSS score of 8 ...

2026-09-22 16:47 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-22 16:47 UTC
Description of the security update for Office 2016: August 11, 2026 ...

web:support.microsoft.com

Be aware that the update in the Microsoft Download Center applies to the Microsoft Installer (.msi)-based edition of Office 2016. It doesn't apply to the Office 2016 Click-to-Run editions, such as Microsoft Office 365 Home. (See What version of Office am I using?) How to get and install the update Method 1: Microsoft Update This update is available from Microsoft Update. When you turn on ...

2026-09-22 16:47 UTC
Update Chrome now to protect against an actively exploited ...

web:www.malwarebytes.com

Chrome issues another monster update, fixing an actively exploited V8 vulnerability and 229 other flaws.

2026-09-22 16:47 UTC
National Vulnerability Database | NIST

web:www.nist.gov

NIST maintains the National Vulnerability Database (NVD), a repository of information on software and hardware flaws that can compromise computer security. This is a key piece of the nation's cybersecurity infrastructure.

2026-09-22 16:47 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-22 16:47 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-22 16:47 UTC

AI Forensic Analysis

Only Available for Registered Users. Sign in to view.

Raw JSON

The full cvelistV5 record. Download as CVE-2026-58491.json.

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "warpgate",
          "vendor": "warp-tech",
          "versions": [
            {
              "status": "affected",
              "version": "< 0.25.5"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 9.3,
            "baseSeverity": "CRITICAL",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-21T18:48:03.982Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/warp-tech/warpgate/security/advisories/GHSA-3c3w-75j2-7h74",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/warp-tech/warpgate/security/advisories/GHSA-3c3w-75j2-7h74"
        },
        {
          "name": "https://github.com/warp-tech/warpgate/commit/eab0548f018d95b5f96f8e913527000e05ed93a2",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/warp-tech/warpgate/commit/eab0548f018d95b5f96f8e913527000e05ed93a2"
        },
        {
          "name": "https://github.com/warp-tech/warpgate/releases/tag/v0.25.5",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/warp-tech/warpgate/releases/tag/v0.25.5"
        }
      ],
      "source": {
        "advisory": "GHSA-3c3w-75j2-7h74",
        "discovery": "UNKNOWN"
      },
      "title": "Warpgate: Reflected XSS in SSO return endpoint via attacker-controlled next parameter"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-58491",
    "datePublished": "2026-09-21T18:48:03.982Z",
    "dateReserved": "2026-06-30T20:21:25.812Z",
    "dateUpdated": "2026-09-21T18:48:03.982Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}