{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "1.77.0"
              },
              {
                "fixed": "1.107.6"
              },
              {
                "introduced": "2.0.0b1"
              },
              {
                "fixed": "2.44.0"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "a282bcade2c2a75847806bbba9cf511dd0623019"
            },
            {
              "introduced": "6001a4549018ad5509f2c11ed6c38d2385159506"
            },
            {
              "fixed": "7ee27e38ab2e525ca60ff1a25d16413ff989fd79"
            },
            {
              "fixed": "9fdabb4b2afb54ff7deb9013f6b43971324d9181"
            },
            {
              "fixed": "490335f8e2322e143a79337ddca9410e0176c812"
            },
            {
              "fixed": "a9dab92099d0ef9d5d4aa34ccac8a6f1b0e51284"
            },
            {
              "fixed": "c1f212a084cbfa0012f2044cdb4731d214b3b983"
            }
          ],
          "repo": "https://github.com/pydantic/pydantic-ai",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-22h6-qm39-v87j"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1289",
      "CWE-918"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107288.json"
  },
  "details": "Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.77.0 until 1.107.6 and 2.44.0, the local web_fetch_tool and the WebFetch local fallback compare blocked_domains entries with a URL hostname before both values are normalized to the form used by getaddrinfo. An attacker-influenced model can use an equivalent IDNA spelling, non-ASCII label separator, case variation, or trailing root label that resolves to a blocked host but does not match the configured string, causing the application to fetch that host with its own privileges. allowed_domains fails closed for unmatched spellings, and private-IP and cloud-metadata protections remain effective. This issue is fixed in versions 1.107.6 and 2.44.0.",
  "id": "CVE-2026-107288",
  "modified": "2026-10-10T02:30:50.740202239Z",
  "published": "2026-10-08T15:18:40.047Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/releases/tag/v2.44.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107288.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-22h6-qm39-v87j"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-107288"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/commit/490335f8e2322e143a79337ddca9410e0176c812"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/commit/a9dab92099d0ef9d5d4aa34ccac8a6f1b0e51284"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/commit/c1f212a084cbfa0012f2044cdb4731d214b3b983"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/pull/8407"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/pull/8409"
    },
    {
      "type": "FIX",
      "url": "https://github.com/pydantic/pydantic-ai/pull/8421"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Pydantic AI: web_fetch_tool blocked_domains bypass via a hostname the resolver normalizes differently"
}