Live › vulnerability › CVE-2026-54249
Go to dashboardPydantic AI UI adapters forward client-submitted UploadedFile references (provider file IDs or s3:// and gs:// URIs) to the model provider without validation. An attacker who can submit message history can make the server's own credentials fetch files the attacker should not read.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 19:11 UTC, 5h before NVD. All times on this page are UTC.
| Product | Ecosystem | Affected | Fixed in |
|---|
| pydantic-ai-slim | pypi | >= 1.65.0, < 1.106.0 | 1.106.0 |
| pydantic-ai-slim | pypi | >= 2.0.0b1, < 2.0.0b6 | 2.0.0b6 |
| pydantic-ai | pypi | >= 1.65.0, < 1.106.0 | 1.106.0 |
| pydantic-ai | pypi | >= 2.0.0b1, < 2.0.0b6 | 2.0.0b6 |
| pydantic ai | vendor | >= 1.65.0, < 1.105.0 | 1.105.0 |
| pydantic ai | vendor | = 2.0.0 | – |
Check the pydantic-ai-slim or pydantic-ai version in the lockfile or pip freeze; affected if >=1.65.0 <1.106.0 or >=2.0.0b1 <2.0.0b6.
1.106.0 (1.x line) or 2.0.0b6 (2.x beta line)Each row is the first time that source carried this signal. The analyst’s rows are its own findings.
A client that can submit message history to a Pydantic AI UI adapter can reference arbitrary files in the application's model-provider or cloud-storage account. The server forwards the reference to the model provider, which fetches it using the server's own credentials, allowing the client to read files it should not have access to.
UI adapters reconstruct file parts from client-submitted message history and forward them to the model provider. File URL parts are validated against a scheme allowlist before being forwarded, but UploadedFile references — which point to a file by provider file ID or cloud-storage URI (e.g. s3://…, gs://…) — were forwarded without validation.
Because the provider resolves an UploadedFile using the server-side identity (IAM role, service account, or provider API key) rather than the client's, a client that crafts message history containing an attacker-chosen UploadedFile can cause the server to read objects belonging to its own account or to other tenants, given a referenceable identifier.
Applications that pass untrusted client-submitted message history to an agent through a UI adapter (such as the Vercel AI adapter). Exploitation requires the attacker to reference a valid file identifier; depending on how the application names objects, such identifiers are not always unguessable.
Upgrade to 1.106.0 (1.x) or 2.0.0b6 (the 2.x beta line), which validate UploadedFile references on client-submitted messages the same way file URLs are validated.
If users cannot upgrade, do not pass untrusted client-submitted message history to the agent, or strip UploadedFile parts from incoming messages before running the agent.
This page as .md · .json · in your agent: get_signal("CVE-2026-54249")
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