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Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header

Type: advisorySources: OSV

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 2.30.0, the Agent.to_web() and clai web development chat server does not validate the Host header, allowing a website visited by a developer to use DNS rebinding to reach a loopback-hosted agent as a same-origin service. The hostile page can read the served UI and submit chat requests that execute agent tools with the local process's privileges and credentials, causing data disclosure or unwanted side effects. Binding to localhost, Origin checks, and CSRF tokens do not prevent the same-origin DNS rebinding path. This issue is fixed in versions 1.107.5 and 2.30.0.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-107292
Confirmed fixed CVEs
Not specified
Updated in this feed
2 Nov 2026, 16:25 UTC · Revision 1

Source evidence

Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header

core-osv · Original source

Published 8 Oct 2026, 16:26 UTC

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 2.30.0, the Agent.to_web() and clai web development chat server does not validate the Host header, allowing a website visited by a developer to use DNS rebinding to reach a loopback-hosted agent as a same-origin service. The hostile page can read the served UI and submit chat requests that execute agent tools with the local process's privileges and credentials, causing data disclosure or unwanted side effects. Binding to localhost, Origin checks, and CSRF tokens do not prevent the same-origin DNS rebinding path. This issue is fixed in versions 1.107.5 and 2.30.0.

osv:CVE-2026-107292
Complete source record
{
  "id": "06a87912ed688e8c8e37aaa42d0a99240d9a0e44f3eca756121b0eb243a51847",
  "url": "https://osv.dev/vulnerability/CVE-2026-107292",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Pydantic AI Web chat UI (`Agent.to_web()`, `clai web`): the local chat endpoint does not validate the `Host` header",
    "summary": "Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. From 1.34.0 until 2.30.0, the Agent.to_web() and clai web development chat server does not validate the Host header, allowing a website visited by a developer to use DNS rebinding to reach a loopback-hosted agent as a same-origin service. The hostile page can read the served UI and submit chat requests that execute agent tools with the local process's privileges and credentials, causing data disclosure or unwanted side effects. Binding to localhost, Origin checks, and CSRF tokens do not prevent the same-origin DNS rebinding path. This issue is fixed in versions 1.107.5 and 2.30.0.",
    "evidence": "osv:CVE-2026-107292",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-107292",
      "aliases": [
        "CVE-2026-107292",
        "GHSA-q2xc-rrxj-58x9",
        "PYSEC-2026-4279",
        "PYSEC-2026-4288"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:H/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/pydantic/pydantic-ai",
              "type": "GIT",
              "events": [
                {
                  "introduced": "afde1c431371ce24757179ed1cad09af0f382d29"
                },
                {
                  "fixed": "394cc1d31656620704a703a2daed752afa5135fe"
                },
                {
                  "introduced": "e19e18065a13be0490483ad3c5601d232af8185b"
                },
                {
                  "fixed": "c24a9008a8fbd752ddf02870c7c4b3a518dbd8c9"
                },
                {
                  "fixed": "871c7aeec5dfed2138655ccbccbf15c6d763bae7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:pydantic:pydantic_ai:*:*:*:*:*:python:*:*",
                    "range": [
                      {
                        "introduced": "1.34.0"
                      },
                      {
                        "fixed": "1.107.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:pydantic:pydantic_ai:*:-:*:*:*:python:*:*",
                    "range": [
                      {
                        "introduced": "2.0.0"
                      },
                      {
                        "fixed": "2.30.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "394cc1d31656620704a703a2daed752afa5135fe"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "871c7aeec5dfed2138655ccbccbf15c6d763bae7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "394cc1d31656620704a703a2daed752afa5135fe"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v1.107.5"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c24a9008a8fbd752ddf02870c7c4b3a518dbd8c9"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v2.30.0"
                  }
                ]
              }
            }
          ],
          "versions": [
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            "v2.29.0",
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          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-107292.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:20.817966999Z",
      "provider": "osv",
      "references": [
        "https://github.com/pydantic/pydantic-ai/releases/tag/v1.107.5",
        "https://github.com/pydantic/pydantic-ai/releases/tag/v2.30.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107292.json",
        "https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-q2xc-rrxj-58x9",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-107292",
        "https://github.com/pydantic/pydantic-ai/commit/394cc1d31656620704a703a2daed752afa5135fe",
        "https://github.com/pydantic/pydantic-ai/commit/871c7aeec5dfed2138655ccbccbf15c6d763bae7",
        "https://github.com/pydantic/pydantic-ai/pull/7437",
        "https://github.com/pydantic/pydantic-ai/pull/7438"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-346",
          "CWE-350"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/107xxx/CVE-2026-107292.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-107292",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487064,
  "published_at": "2026-10-08T16:26:48.144+00:00"
}