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Response snapshot Oct 27, 2026, 02:47 UTC

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VulnerabilityCVE-2026-54249

Pydantic AI: Unvalidated UploadedFile references in UI adapters allow server-side file access using the application's credentials

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.

At a glance

Exploited
Not known
Severity
6.8 Medium (CVSS 3.1)
Chance of exploitation
0.3% in the next 30 days
Sources
1 source

What to do

GitHub lists first patched versions: pydantic-ai-slim: 1.106.0; pydantic-ai-slim: 2.0.0b6; pydantic-ai: 1.106.0; pydantic-ai: 2.0.0b6. Confirm the affected range and upgrade guidance in the exact advisory.

Read GitHub-reviewed advisory GHSA-h7p7-w5gc-xj3w (opens a new tab)

What happened

### Summary

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.

### Details

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.

Continue reading

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.

### Impact

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.

### Patches

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.

### Workarounds

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.

Affected package ranges reported by GitHub: pydantic-ai-slim: >= 1.65.0, < 1.106.0 pydantic-ai-slim: >= 2.0.0b1, < 2.0.0b6 pydantic-ai: >= 1.65.0, < 1.106.0 pydantic-ai: >= 2.0.0b1, < 2.0.0b6

Scores and how they were measured

CVSS base severity

6.8

Version 3.1As of

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

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.3%

Scored Percentile 24.2%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    GitHub-reviewed advisory GHSA-h7p7-w5gc-xj3w (opens a new tab)

    The public advisory supplies the description, affected package/version ranges, and any listed CVSS metric. GitHub review is not local review.

    Published Checked

  2. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  3. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  4. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  5. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  6. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  7. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  8. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  9. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  10. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  11. Primary source

    GitHub public advisory API page (opens a new tab)

    The API page supplied GHSA-h7p7-w5gc-xj3w, its actual identifiers, source dates, and structured metrics.

    Published Date not suppliedChecked

  12. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-54249, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 22). Pydantic AI: Unvalidated UploadedFile references in UI adapters allow server-side file access using the application's credentials (CVE-2026-54249). https://kevwire.com/record/CVE-2026-54249

MLA

"Pydantic AI: Unvalidated UploadedFile references in UI adapters allow server-side file access using the application's credentials (CVE-2026-54249)." KEVWire, 22 Oct. 2026, kevwire.com/record/CVE-2026-54249.

Chicago

KEVWire. "Pydantic AI: Unvalidated UploadedFile references in UI adapters allow server-side file access using the application's credentials (CVE-2026-54249)." Last modified October 22, 2026. https://kevwire.com/record/CVE-2026-54249.

Evidence summary (plain text)

Pydantic AI: Unvalidated UploadedFile references in UI adapters allow server-side file access using the application's credentials (Aug 13, 2026).
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.
CVSS 6.8 (version 3.1; evidence as of Oct 22, 2026; https://github.com/advisories/GHSA-h7p7-w5gc-xj3w).
EPSS 0.3% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-54249&date=2026-10-26).
Sources:
GitHub-reviewed advisory GHSA-h7p7-w5gc-xj3w: https://github.com/advisories/GHSA-h7p7-w5gc-xj3w
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQxNTo1Mjo1NlrOAAfxiA%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yMlQxNDowNjoxNFrOAAfxZw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NzoxN1rOAAf0Kg%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NTozNlrOAAf0Jw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0NTowNVrOAAf0JQ%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0Mzo0NVrOAAf0Iw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QyMDo0MzozMVrOAAf0Ig%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODozNTowMVrOAAZRcw%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODozMDoyN1rOAAY_5Q%3D%3D
GitHub public advisory API page: https://api.github.com/advisories?type=reviewed&per_page=100&sort=updated&direction=desc&after=Y3Vyc29yOnYyOpK0MjAyNi0xMC0yM1QxODoyOTowNVrOAAfz8g%3D%3D
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-54249&date=2026-10-26
Record ID: CVE-2026-54249.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 27, 2026, 01:40 UTC. Ingestion is not an independent editorial investigation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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