follow-redirects sensitiveHeaders regex escaping can expose credential headers

{
  "id": "9875e1e4dfbcc3237b41508676dde1cdc74e31ab66a2c87e7615f5d9b3782ce8",
  "url": "https://osv.dev/vulnerability/GHSA-8r9p-f939-6h3c",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "follow-redirects sensitiveHeaders regex escaping can expose credential headers",
    "summary": "### Summary follow-redirects 1.16.0 introduced the `sensitiveHeaders` option (the fix for CVE-2026-40895 / GHSA-r4q5-vmmm-2653), which lets an application declare extra header names that must be removed when a redirect crosses to a different host or downgrades protocol. The filter is a single case-insensitive regular expression built by concatenating the declared header names into an alternation after passing each through `escapeRegex`. `escapeRegex` escapes only a partial set of metacharacters and leaves `^`, `|`, `[`, `{`, and `}` unescaped. Header names may legitimately contain `^` and `|` (both are valid RFC 9110 token characters that Node accepts and sends), and for a declared name containing either, the generated pattern can never match the intended header. As a result, an application that adopts this option to protect a custom credential header, then follows an attacker-controlled cross-origin redirect, forwards that credential to the attacker with no error or warning, while believing it is protected. The failure is silent: the protection simply does not exist for the affected names. The built-in list (Authorization, Proxy-Authorization, Cookie) contains no metacharacters and is not affected by this defect. ### Details The filter is constructed once, in the `RedirectableRequest` constructor at `index.js:118-120`: ```js this._headerFilter = new RegExp(\"^(?:\" + sensitiveHeaders.concat(options.sensitiveHeaders).map(escapeRegex).join(\"|\") + \")$\", \"i\"); ``` `escapeRegex` at",
    "evidence": "osv:GHSA-8r9p-f939-6h3c",
    "products": [
      {
        "name": {
          "value": "follow-redirects",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "1.16.1",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-8r9p-f939-6h3c",
      "aliases": [
        "CVE-2026-111755",
        "GHSA-8r9p-f939-6h3c"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "1.16.0"
                },
                {
                  "fixed": "1.16.1"
                }
              ]
            }
          ],
          "package": {
            "name": "follow-redirects",
            "purl": "pkg:npm/follow-redirects",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-8r9p-f939-6h3c/GHSA-8r9p-f939-6h3c.json"
          }
        }
      ],
      "modified": "2026-10-20T18:00:04.701467015Z",
      "provider": "osv",
      "references": [
        "https://github.com/follow-redirects/follow-redirects/security/advisories/GHSA-8r9p-f939-6h3c",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-111755",
        "https://github.com/follow-redirects/follow-redirects/commit/080a76d0e125b37bf81717368a61d5dc37aa56c8",
        "https://github.com/follow-redirects/follow-redirects",
        "https://github.com/follow-redirects/follow-redirects/releases/tag/v1.16.1"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-185",
          "CWE-200"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": "2026-10-19T18:17:00Z",
        "github_reviewed_at": "2026-10-20T17:53:05Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-111755",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 390128,
  "published_at": "2026-10-20T17:53:05+00:00"
}