Vulnerability-Lookup

GHSA-WQVH-63MV-9W92

Vulnerability from github – Published: 2026-03-12 14:50 – Updated: 2026-03-13 13:35

Summary

@backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass

Details

Impact

The experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected.

A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token.

This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default.

Patches

Upgrade to @backstage/plugin-auth-backend version 0.27.1 or later.

Workarounds

Disable experimental Dynamic Client Registration and Client ID Metadata Documents features if they are not required.

References

RFC 6749 Section 3.1.2 - Redirection Endpoint

Severity ?

5.9 (Medium)


                  
                    CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@backstage/plugin-auth-backend"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.27.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32235"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-20",
      "CWE-601"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-12T14:50:59Z",
    "nvd_published_at": "2026-03-12T19:16:17Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nThe experimental OIDC provider in `@backstage/plugin-auth-backend` is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured `allowedRedirectUriPatterns` are affected.\n\nA specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token.\n\nThis requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default.\n\n### Patches\n\nUpgrade to `@backstage/plugin-auth-backend` version 0.27.1 or later.\n\n### Workarounds\n\nDisable experimental Dynamic Client Registration and Client ID Metadata Documents features if they are not required.\n\n### References\n\n- [RFC 6749 Section 3.1.2 - Redirection Endpoint](https://datatracker.ietf.org/doc/html/rfc6749#section-3.1.2)",
  "id": "GHSA-wqvh-63mv-9w92",
  "modified": "2026-03-13T13:35:42Z",
  "published": "2026-03-12T14:50:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/security/advisories/GHSA-wqvh-63mv-9w92"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32235"
    },
    {
      "type": "WEB",
      "url": "https://github.com/backstage/backstage/commit/6042dd0c7f0706e0f473dafa92799ecf19c825ec"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/backstage/backstage"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "@backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass"
}

CVE-2026-32235 (GCVE-0-2026-32235)

Vulnerability from cvelistv5 – Published: 2026-03-12 18:35 – Updated: 2026-03-12 20:46

Title

@backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass

Summary

Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1.

Severity ?

5.9 (Medium)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N

CWE

CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

Assigner

GitHub_M

References

URL

Tags

https://github.com/backstage/backstage/security/a…

x_refsource_CONFIRM

Impacted products

	Vendor	Product	Version
	@backstage	plugin-auth-backend	Affected: < 0.27.1

Show details on NVD website

JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-32235",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-03-12T20:38:14.280151Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-03-12T20:46:46.618Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "plugin-auth-backend",
          "vendor": "@backstage",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.27.1"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Backstage is an open framework for building developer portals. Prior to 0.27.1, the experimental OIDC provider in @backstage/plugin-auth-backend is vulnerable to a redirect URI allowlist bypass. Instances that have enabled experimental Dynamic Client Registration or Client ID Metadata Documents and configured allowedRedirectUriPatterns are affected. A specially crafted redirect URI can pass the allowlist validation while resolving to an attacker-controlled host. If a victim approves the resulting OAuth consent request, their authorization code is sent to the attacker, who can exchange it for a valid access token. This requires victim interaction and that one of the experimental features is explicitly enabled, which is not the default. This vulnerability is fixed in 0.27.1."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 5.9,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-601",
              "description": "CWE-601: URL Redirection to Untrusted Site (\u0027Open Redirect\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-03-12T18:35:06.325Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/backstage/backstage/security/advisories/GHSA-wqvh-63mv-9w92",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/backstage/backstage/security/advisories/GHSA-wqvh-63mv-9w92"
        }
      ],
      "source": {
        "advisory": "GHSA-wqvh-63mv-9w92",
        "discovery": "UNKNOWN"
      },
      "title": "@backstage/plugin-auth-backend: OAuth redirect URI allowlist bypass"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-32235",
    "datePublished": "2026-03-12T18:35:06.325Z",
    "dateReserved": "2026-03-11T14:47:05.683Z",
    "dateUpdated": "2026-03-12T20:46:46.618Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-WQVH-63MV-9W92

Impact

Patches

Workarounds

References

CVE-2026-32235 (GCVE-0-2026-32235)

Tags

Sightings

Nomenclature