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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-03-12 20:38 UTC

CWE

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

Assigner

GitHub_M mitre root

References

1 reference

URL	Tags
https://github.com/backstage/backstage/security/a…	x_refsource_CONFIRM

Impacted products

1 product

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

Show details on NVD website

JSON

To clipboard

{
  "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	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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Action not permitted

GHSA-WQVH-63MV-9W92

Impact

Patches

Workarounds

References

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

Tags

Sightings

Nomenclature

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