{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "4.8.0"
              },
              {
                "fixed": "4.14.2"
              },
              {
                "introduced": "5.0.0-rc.0"
              },
              {
                "fixed": "5.0.0-rc.13"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "cf2095dda5d489ee37166cfce0905f6bd21f4761"
            },
            {
              "fixed": "5a32a74e99d38b58d5b7e94c986c96356d5cd3e3"
            },
            {
              "introduced": "6767fe27eb952e5bc09aa2e5a7d8f96f5a1c424a"
            },
            {
              "fixed": "d1dc61ad0e5034ee3d41dce6cf83eea94dcd46d3"
            },
            {
              "fixed": "0bd5199db066be22b2ca1ec8bc6109e5d62e6070"
            },
            {
              "fixed": "62719710790a150a9eacab9c0a066e0d122d15be"
            }
          ],
          "repo": "https://github.com/team-alembic/ash_authentication",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-54fc-x3hv-ffhw"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-79"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66882.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "fe0b4558dbe852fee5d81a460a8355577618a8c8"
          },
          {
            "fixed": "*"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Improper Neutralization of Input During Web Page Generation (XSS) vulnerability in team-alembic AshAuthentication allows reflected cross-site scripting via the confirmation and magic link interaction forms.\n\nWhen a strategy is configured with require_interaction? set to true, AshAuthentication serves an intermediate HTML page asking the user to confirm the action by submitting a form. Both such pages embed a request parameter directly into a hidden input's value attribute without HTML escaping: lib/ash_authentication/add_ons/confirmation/confirmation_form.html.eex interpolates the confirm parameter, and lib/ash_authentication/strategies/magic_link/sign_in_form.html.eex interpolates the magic link token parameter. These templates are compiled with EEx.function_from_file/3 using plain \u003c%= %\u003e expressions, which perform no escaping, so the parameter is reflected verbatim.\n\nNeither accept handler validates the value before rendering it. AshAuthentication.AddOn.Confirmation.Plug.accept/2 only checks that a confirm key is present, and AshAuthentication.Strategy.MagicLink.Plug.accept/2 reads the parameter directly, so no token signature is verified at this stage and arbitrary attacker-supplied text reaches the template. An unauthenticated attacker can therefore craft a URL whose parameter terminates the attribute and injects markup, for example a quote followed by a \u003cscript\u003e element. Because the accept phase is served over GET, loading the crafted link is sufficient; no form submission or prior authentication is required.\n\nThe injected script executes in the origin of the application embedding AshAuthentication, giving it access to that origin's cookies, session, and same-origin responses. Since these pages are part of the authentication flow, a victim following what appears to be a legitimate confirmation or sign-in link is a plausible target.\n\nThis issue affects ash_authentication: from 4.8.0 before 4.14.2 and from 5.0.0-rc.0 before 5.0.0-rc.13.",
  "id": "CVE-2026-66882",
  "modified": "2026-08-30T11:30:16.069472083Z",
  "published": "2026-08-25T08:03:47.721Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-66882.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-66882"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66882.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/team-alembic/ash_authentication/security/advisories/GHSA-54fc-x3hv-ffhw"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-66882"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/0bd5199db066be22b2ca1ec8bc6109e5d62e6070"
    },
    {
      "type": "FIX",
      "url": "https://github.com/team-alembic/ash_authentication/commit/62719710790a150a9eacab9c0a066e0d122d15be"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/team-alembic/ash_authentication"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Reflected XSS in AshAuthentication confirmation and magic link interaction forms"
}