{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "fixed": "4.24.15"
              },
              {
                "introduced": "5.0.0-beta.4"
              },
              {
                "fixed": "5.0.0-beta.32"
              },
              {
                "introduced": "0.1.0"
              },
              {
                "fixed": "0.41.3"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "introduced": "0126f94788a263bd8420ceac9a11ed6d2c2fb958"
            },
            {
              "introduced": "8e771a2993437125ae21883f76eb81cbb02788b8"
            },
            {
              "fixed": "d857eec560fb99c8b18d3b22a2693b849a62d1c3"
            },
            {
              "fixed": "e293b3746616660f0844347a68d09eac54b95c6f"
            },
            {
              "fixed": "5af7357fb40c82e0c66f940319321260ddfd44dc"
            },
            {
              "fixed": "19d2feb24359fa8c79418907fc68d9ec8152ca94"
            },
            {
              "fixed": "a63eee12a1a20cb35209e44195b097868517b9a0"
            }
          ],
          "repo": "https://github.com/nextauthjs/next-auth",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-7rqj-j65f-68wh"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-180"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73420.json"
  },
  "details": "NextAuth.js provides authentication for Next.js. Prior to @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32, the defaultNormalizer used by the email and magic-link sign-in flow validates an address before applying Unicode normalization. An address can contain a Unicode character such as U+FF20 FULLWIDTH COMMERCIAL AT that is not ASCII at-sign but canonicalizes to an ASCII at-sign under NFKC or NFKD normalization. The address passes the normalizer's single-at-sign check, but a downstream sendVerificationRequest mail library or delivery service that normalizes the address can then see two at-sign separators and deliver the passwordless sign-in link to an attacker-controlled recipient. Applications are affected when the email provider uses the built-in normalizer rather than a custom normalizeIdentifier and the downstream sender applies Unicode normalization. An attacker who knows a victim's email address can request the misrouted magic link and sign in as the victim without victim interaction. This issue is fixed in @auth/core 0.41.3 and next-auth 4.24.15 and 5.0.0-beta.32.",
  "id": "CVE-2026-73420",
  "modified": "2026-08-16T03:31:30.066626041Z",
  "published": "2026-08-13T22:04:15.414Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/nextauthjs/next-auth/releases/tag/@auth/core@0.41.3"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nextauthjs/next-auth/releases/tag/next-auth@4.24.15"
    },
    {
      "type": "WEB",
      "url": "https://github.com/nextauthjs/next-auth/releases/tag/next-auth@5.0.0-beta.32"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/73xxx/CVE-2026-73420.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/nextauthjs/next-auth/security/advisories/GHSA-7rqj-j65f-68wh"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73420"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextauthjs/next-auth/commit/19d2feb24359fa8c79418907fc68d9ec8152ca94"
    },
    {
      "type": "FIX",
      "url": "https://github.com/nextauthjs/next-auth/commit/a63eee12a1a20cb35209e44195b097868517b9a0"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "NextAuth.js: Email normalizer validates the address before Unicode normalization, allowing a homoglyph @ bypass"
}