Vulnerability-Lookup

GHSA-JQCG-44MW-7W3H

Vulnerability from github – Published: 2026-10-05 23:30 – Updated: 2026-10-05 23:30

Summary

proxy-addr vulnerable to IP spoofing via IPv4-mapped IPv6 trust subnet

Details

Impact

proxy-addr determines which network hops are trusted proxies so that X-Forwarded-For can be believed. When an application configures a trust subnet as an IPv4-mapped IPv6 address with a short prefix, such as ::ffff:10.0.0.0/8 (the correct spelling is ::ffff:10.0.0.0/104), the subnet compiles with all-zero leading bits and matches every IPv4 address instead of the block it names. The same happens for any IPv6 trust subnet with zero leading bits, such as ::/1.

Every unauthenticated client is then trusted as a proxy at hop 0, so proxyaddr(req, trust), and therefore req.ip and req.ips in Express, returns whatever the client sends in X-Forwarded-For. This defeats IP-based access control, rate limiting, geolocation, and audit logging. The misconfiguration compiles without any error, and the same block written correctly behaves correctly, so the difference is not visible from the configuration.

Patches

Upgrade to proxy-addr 2.0.8. An IPv4 address now matches an IPv6 trust subnet only when that subnet is a genuine IPv4-mapped subnet whose prefix covers the mapped marker.

Workarounds

Write IPv4 trust subnets in plain IPv4 notation (for example 10.0.0.0/8). If IPv4-mapped IPv6 notation is required, use the full form so the prefix covers the mapped marker (for example ::ffff:10.0.0.0/104 for the 10.0.0.0/8 block).

Severity

9.1 (Critical)


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

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JSON

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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "proxy-addr"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.1.0"
            },
            {
              "fixed": "2.0.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-90711"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-290",
      "CWE-348",
      "CWE-697"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-05T23:30:26Z",
    "nvd_published_at": "2026-09-15T07:16:33Z",
    "severity": "CRITICAL"
  },
  "details": "### Impact\n\n`proxy-addr` determines which network hops are trusted proxies so that `X-Forwarded-For` can be believed. When an application configures a trust subnet as an IPv4-mapped IPv6 address with a short prefix, such as `::ffff:10.0.0.0/8` (the correct spelling is `::ffff:10.0.0.0/104`), the subnet compiles with all-zero leading bits and matches every IPv4 address instead of the block it names. The same happens for any IPv6 trust subnet with zero leading bits, such as `::/1`.\n\nEvery unauthenticated client is then trusted as a proxy at hop 0, so `proxyaddr(req, trust)`, and therefore `req.ip` and `req.ips` in Express, returns whatever the client sends in `X-Forwarded-For`. This defeats IP-based access control, rate limiting, geolocation, and audit logging. The misconfiguration compiles without any error, and the same block written correctly behaves correctly, so the difference is not visible from the configuration.\n\n### Patches\n\nUpgrade to `proxy-addr` 2.0.8. An IPv4 address now matches an IPv6 trust subnet only when that subnet is a genuine IPv4-mapped subnet whose prefix covers the mapped marker.\n\n### Workarounds\n\nWrite IPv4 trust subnets in plain IPv4 notation (for example `10.0.0.0/8`). If IPv4-mapped IPv6 notation is required, use the full form so the prefix covers the mapped marker (for example `::ffff:10.0.0.0/104` for the `10.0.0.0/8` block).",
  "id": "GHSA-jqcg-44mw-7w3h",
  "modified": "2026-10-05T23:30:27Z",
  "published": "2026-10-05T23:30:26Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/jshttp/proxy-addr/security/advisories/GHSA-jqcg-44mw-7w3h"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90711"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jshttp/proxy-addr/commit/780911d84d18e2c5fa008ed0c0d387631ec11965"
    },
    {
      "type": "WEB",
      "url": "https://cna.openjsf.org/security-advisories.html"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/jshttp/proxy-addr"
    },
    {
      "type": "WEB",
      "url": "https://github.com/jshttp/proxy-addr/releases/tag/v2.0.8"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "proxy-addr vulnerable to IP spoofing via IPv4-mapped IPv6 trust subnet"
}

CVE-2026-90711 (GCVE-0-2026-90711)

Vulnerability from cvelistv5 – Published: 2026-09-15 06:19 – Updated: 2026-09-15 14:48

Title

proxy-addr vulnerable to IP spoofing via IPv4-mapped IPv6 trust subnet

Summary

proxy-addr is a Node.js module that determines a request's client address behind trusted reverse proxies, and it backs Express req.ip and req.ips. In versions 1.1.0 through 2.0.7, a trust subnet written in IPv4-mapped IPv6 notation with an IPv4-sized prefix, such as ::ffff:10.0.0.0/8 instead of the correct ::ffff:10.0.0.0/104, is accepted without error but trusts every IPv4 address on the internet rather than the block it names. Because the socket peer then becomes trusted at hop 0, any unauthenticated client can supply an arbitrary X-Forwarded-For header and control the address the application reads, which defeats IP-based access control, rate limiting, geolocation, and audit logging. This is a fail-open regression introduced in version 1.1.0. The issue is fixed in proxy-addr 2.0.8, and users should upgrade to 2.0.8 or later. As a workaround, ensure any IPv4-mapped IPv6 trust subnet uses a prefix length of at least 97, or express the range in plain IPv4 notation.

Severity

9.1 (Critical)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-15 14:46 UTC

CWE

CWE-290 - Authentication Bypass by Spoofing
CWE-348 - Use of Less Trusted Source
CWE-697 - Incorrect Comparison

Assigner

openjs CNA under the redhat root

CNA scorecard C 65/100 over 100 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/jshttp/proxy-addr/security/adv…
https://cna.openjsf.org/security-advisories.html

Impacted products

1 product

Vendor	Product	Version
proxy-addr	proxy-addr	Affected: 1.1.0 , < 2.0.8 (semver) Unaffected: 2.0.8 (semver)

Credits

kagebunsher UlisesGascon kustundag

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

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Confirmed: The vulnerability has been validated from an analyst's perspective.
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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.

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