Vulnerability-Lookup

GHSA-CG7W-RG45-PC59

Vulnerability from github – Published: 2026-06-26 19:17 – Updated: 2026-06-26 19:17

Summary

pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)

Details

Summary

When an application using Pydantic AI opts a URL into force_download='allow-local' (which disables the default block on private/internal IPs) and runs on a network that routes the affected IPv6 transition forms (NAT64- or ISATAP-configured networks), the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form that the previous fix did not decode — IPv4-compatible IPv6 (::a.b.c.d), the NAT64 RFC 8215 local-use prefix (64:ff9b:1::/48), operator-chosen NAT64 prefixes, or ISATAP. The IPv6 wrapper is then delivered to the underlying IPv4 metadata endpoint, exposing cloud IAM short-term credentials.

The bypass is exploitable only in environments whose network actually routes these forms — NAT64-configured networks (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or networks with an ISATAP tunnel for ISATAP. A standard dual-stack cloud VM or container does not route them and is not affected in practice. The IPv4-compatible and Teredo variants are deprecated and addressed as defense-in-depth.

This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580). The prior remediation decoded only IPv4-mapped IPv6, 6to4, and the NAT64 well-known prefix; the metadata guarantee did not hold for the remaining transition forms.

Severity

MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N = 6.8

Same impact metrics and narrow attack surface as the parent advisory (AC:H): exploitation requires the application to have opted into allow-local on a URL influenced by untrusted input, and the NAT64/ISATAP variants additionally require the deployment network to route those forms.

CWE-918: Server-Side Request Forgery (SSRF)

Affected Versions

Package	Vulnerable	Patched
`pydantic-ai`	`>= 1.56.0, < 1.102.0`; `>= 2.0.0b1, < 2.0.0b3`	`1.102.0`; `2.0.0b3`
`pydantic-ai-slim`	`>= 1.56.0, < 1.102.0`; `>= 2.0.0b1, < 2.0.0b3`	`1.102.0`; `2.0.0b3`

These transition forms have not been decoded since SSRF protection was introduced in 1.56.0.

Who Is Affected

Users are affected only if their application explicitly opts a FileUrl (ImageUrl, AudioUrl, VideoUrl, DocumentUrl) into force_download='allow-local' on a URL that is, or could be, influenced by untrusted input.

Beyond that precondition, the affected encodings only reach a metadata endpoint in environments whose network actually routes them. The broadly-routable IPv4-mapped form was addressed in 1.99.0 (CVE-2026-46678); the additional forms addressed here require a NAT64-configured network (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or an ISATAP tunnel for the ISATAP variant. The IPv4-compatible and Teredo forms are deprecated and not routed by modern stacks; they are addressed as defense-in-depth. Most deployments on a standard dual-stack cloud VM or container are therefore not exploitable in practice, but the fix restores the "always blocked" guarantee for the environments that are.

Users are not affected if they use any of the bundled integrations to ingest user input, because they do not propagate force_download from external data:

Agent.to_web / clai web
VercelAIAdapter
AGUIAdapter / Agent.to_ag_ui

Applications that only download from developer-controlled URLs are not affected.

Remediation

Upgrade to 1.102.0 or later (or 2.0.0b3 or later on the 2.0 pre-release line). The cloud-metadata and private-IP blocklists now decode the embedded IPv4 of every standardized IPv6 transition form before evaluating it — IPv4-mapped, IPv4-compatible, 6to4, NAT64 across all prefix lengths (including the RFC 8215 local-use prefix and operator-chosen prefixes), ISATAP, and Teredo. The set of always-blocked cloud metadata/credential endpoints has also been expanded across providers.

Workaround for Unpatched Versions

Avoid passing force_download='allow-local' on any URL that could be influenced by untrusted input. If developers must, resolve the hostname themselves and validate the result against their own metadata blocklist — including IPv6 transition forms — before constructing the FileUrl.

Credits

Reported by @SnailSploit.

Severity

6.8 (Medium)


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

Show details on source website

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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pydantic-ai-slim"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.56.0"
            },
            {
              "fixed": "1.102.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pydantic-ai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "1.56.0"
            },
            {
              "fixed": "1.102.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pydantic-ai"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0b1"
            },
            {
              "fixed": "2.0.0b3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "pydantic-ai-slim"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.0.0b1"
            },
            {
              "fixed": "2.0.0b3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-48782"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-26T19:17:56Z",
    "nvd_published_at": "2026-06-17T13:20:43Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nWhen an application using Pydantic AI opts a URL into `force_download=\u0027allow-local\u0027` (which disables the default block on private/internal IPs) **and runs on a network that routes the affected IPv6 transition forms (NAT64- or ISATAP-configured networks)**, the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form that the previous fix did not decode \u2014 IPv4-compatible IPv6 (`::a.b.c.d`), the NAT64 RFC 8215 local-use prefix (`64:ff9b:1::/48`), operator-chosen NAT64 prefixes, or ISATAP. The IPv6 wrapper is then delivered to the underlying IPv4 metadata endpoint, exposing cloud IAM short-term credentials.\n\n**The bypass is exploitable only in environments whose network actually routes these forms** \u2014 NAT64-configured networks (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or networks with an ISATAP tunnel for ISATAP. A standard dual-stack cloud VM or container does not route them and is not affected in practice. The IPv4-compatible and Teredo variants are deprecated and addressed as defense-in-depth.\n\nThis is an incomplete fix of [GHSA-cqp8-fcvh-x7r3](https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cqp8-fcvh-x7r3) / [CVE-2026-46678](https://nvd.nist.gov/vuln/detail/CVE-2026-46678) (itself a follow-up to [CVE-2026-25580](https://nvd.nist.gov/vuln/detail/CVE-2026-25580)). The prior remediation decoded only IPv4-mapped IPv6, 6to4, and the NAT64 well-known prefix; the metadata guarantee did not hold for the remaining transition forms.\n\n## Severity\n\n**MEDIUM** \u2014 `CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N` = **6.8**\n\nSame impact metrics and narrow attack surface as the parent advisory (AC:H): exploitation requires the application to have opted into `allow-local` on a URL influenced by untrusted input, and the NAT64/ISATAP variants additionally require the deployment network to route those forms.\n\n**CWE-918**: Server-Side Request Forgery (SSRF)\n\n## Affected Versions\n\n| Package | Vulnerable | Patched |\n|---|---|---|\n| `pydantic-ai` | `\u003e= 1.56.0, \u003c 1.102.0`; `\u003e= 2.0.0b1, \u003c 2.0.0b3` | `1.102.0`; `2.0.0b3` |\n| `pydantic-ai-slim` | `\u003e= 1.56.0, \u003c 1.102.0`; `\u003e= 2.0.0b1, \u003c 2.0.0b3` | `1.102.0`; `2.0.0b3` |\n\nThese transition forms have not been decoded since SSRF protection was introduced in `1.56.0`.\n\n## Who Is Affected\n\nUsers are affected **only if** their application explicitly opts a `FileUrl` (`ImageUrl`, `AudioUrl`, `VideoUrl`, `DocumentUrl`) into `force_download=\u0027allow-local\u0027` on a URL that is, or could be, influenced by untrusted input.\n\nBeyond that precondition, the affected encodings only reach a metadata endpoint in environments whose network actually routes them. The broadly-routable IPv4-mapped form was addressed in `1.99.0` (CVE-2026-46678); the additional forms addressed here require a **NAT64-configured network** (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or an **ISATAP tunnel** for the ISATAP variant. The IPv4-compatible and Teredo forms are deprecated and not routed by modern stacks; they are addressed as defense-in-depth. Most deployments on a standard dual-stack cloud VM or container are therefore not exploitable in practice, but the fix restores the \"always blocked\" guarantee for the environments that are.\n\nUsers are **not** affected if they use any of the bundled integrations to ingest user input, because they do not propagate `force_download` from external data:\n\n- `Agent.to_web` / `clai web`\n- `VercelAIAdapter`\n- `AGUIAdapter` / `Agent.to_ag_ui`\n\nApplications that only download from developer-controlled URLs are not affected.\n\n## Remediation\n\nUpgrade to `1.102.0` or later (or `2.0.0b3` or later on the 2.0 pre-release line). The cloud-metadata and private-IP blocklists now decode the embedded IPv4 of every standardized IPv6 transition form before evaluating it \u2014 IPv4-mapped, IPv4-compatible, 6to4, NAT64 across all prefix lengths (including the RFC 8215 local-use prefix and operator-chosen prefixes), ISATAP, and Teredo. The set of always-blocked cloud metadata/credential endpoints has also been expanded across providers.\n\n## Workaround for Unpatched Versions\n\nAvoid passing `force_download=\u0027allow-local\u0027` on any URL that could be influenced by untrusted input. If developers must, resolve the hostname themselves and validate the result against their own metadata blocklist \u2014 including IPv6 transition forms \u2014 before constructing the `FileUrl`.\n\n## Credits\n\nReported by [@SnailSploit](https://snailsploit.com).",
  "id": "GHSA-cg7w-rg45-pc59",
  "modified": "2026-06-26T19:17:56Z",
  "published": "2026-06-26T19:17:56Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/security/advisories/GHSA-cg7w-rg45-pc59"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-48782"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/pull/5596"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/commit/1add06179ba4de259f7ab977620b697b7209f7e4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/pydantic/pydantic-ai"
    },
    {
      "type": "WEB",
      "url": "https://github.com/pydantic/pydantic-ai/releases/tag/v1.102.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)"
}

CVE-2026-48782 (GCVE-0-2026-48782)

Vulnerability from cvelistv5 – Published: 2026-06-16 22:49 – Updated: 2026-06-17 14:22

Title

pydantic-ai: SSRF blocklist bypass via IPv4-compatible, SIIT/IVI, and local NAT64 IPv6 addresses (incomplete fix of CVE-2026-46678)

Summary

Pydantic AI is a Python agent framework for building applications and workflows with Generative AI. In versions 1.56.0 through 1.101.0, 2.0.0b1, and 2.0.0b2, the cloud-metadata blocklist could be bypassed by encoding the metadata IP in an IPv6 transition form that the previous fix, CVE-2026-46678, did not decode, exposing cloud IAM short-term credentials. The previous remediation decoded only IPv4-mapped IPv6, 6to4, and the NAT64 well-known prefix, so the metadata guarantee did not hold for the remaining transition forms: IPv4-compatible IPv6 (::a.b.c.d), the NAT64 RFC 8215 local-use prefix (64:ff9b:1::/48), operator-chosen NAT64 prefixes, and ISATAP. The IPv6 wrapper is then delivered to the underlying IPv4 metadata endpoint. This occurs when an application using Pydantic AI opts a URL into force_download='allow-local' (which disables the default block on private/internal IPs) and runs on a network that actually routes the affected IPv6 transition forms: NAT64-configured networks (IPv6-only or dual-stack-with-NAT64 deployments, including some Kubernetes setups) for the NAT64 variants, or networks with an ISATAP tunnel for ISATAP. A standard dual-stack cloud VM or container does not route these forms and is not affected in practice. The IPv4-compatible and Teredo variants are deprecated and addressed as defense-in-depth. This is an incomplete fix of GHSA-cqp8-fcvh-x7r3 / CVE-2026-46678 (itself a follow-up to CVE-2026-25580). This issue has been fixed in version 2.0.0b3.

Severity

6.8 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-918 - Server-Side Request Forgery (SSRF)

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/pydantic/pydantic-ai/security/…	x_refsource_CONFIRM
https://github.com/pydantic/pydantic-ai/pull/5596	x_refsource_MISC
https://github.com/pydantic/pydantic-ai/commit/1a…	x_refsource_MISC
https://github.com/pydantic/pydantic-ai/releases/…	x_refsource_MISC

Impacted products

2 products

Vendor	Product	Version
pydantic	pydantic-ai	Affected: >= 1.56.0, < 1.102.0 Affected: >= 2.0.0b1, < 2.0.0b3
pydantic	pydantic-ai-slim	Affected: >= 2.0.0b1, < 2.0.0b3 Affected: >= 1.56.0, < 1.102.0

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JSON

To clipboard

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                "id": "CVE-2026-48782",
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                  },
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                "role": "CISA Coordinator",
                "timestamp": "2026-06-17T14:22:37.373304Z",
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-CG7W-RG45-PC59

Summary

Severity

Affected Versions

Who Is Affected

Remediation

Workaround for Unpatched Versions

Credits

CVE-2026-48782 (GCVE-0-2026-48782)

Tags

Sightings

Nomenclature