Pydantic In 2.10.x AnyUrl does not validate data uris (Fix)

The Fix

pip install pydantic==2.10.3

Based on closed pydantic/pydantic issue #10968 · PR/commit linked

Production note: Most teams hit this during upgrades or environment changes. Roll out with a canary and smoke critical endpoints (health, OpenAPI/docs) before 100%.

Jump to Verify Open PR/Commit

@@ -456,13 +456,13 @@ class AnyUrl(_BaseUrl):
     * Any scheme allowed
     * Top-level domain (TLD) not required
-    * Host required
+    * Host not required

repro.py

pydantic version: 2.10.1
        pydantic-core version: 2.27.1
          pydantic-core build: profile=release pgo=false
                 install path: /private/tmp/pyd/venv/lib/python3.12/site-packages/pydantic
               python version: 3.12.7 (main, Oct  1 2024, 02:05:46) [Clang 15.0.0 (clang-1500.3.9.4)]
                     platform: macOS-15.1-arm64-arm-64bit
             related packages: pydantic-settings-2.6.1 typing_extensions-4.12.2
                       commit: unknown

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

fix.md

Option A — Upgrade to fixed release\npip install pydantic==2.10.3\nWhen NOT to use: Do not use this fix if you require strict host validation for URLs.\n\n

Why This Fix Works in Production

Trigger: pydantic_core._pydantic_core.ValidationError: 1 validation error for function-wrap[wrap_val()]
Mechanism: Fixes the enforcement of host requirement for URLs in AnyUrl to be compatible with v2.9 behavior.
Why the fix works: Fixes the enforcement of host requirement for URLs in AnyUrl to be compatible with v2.9 behavior. (first fixed release: 2.10.3).

Production impact:

If left unfixed, the same config can fail only in production (env differences), causing startup failures or partial feature outages.

Why This Breaks in Prod

Shows up under Python 3.12 in real deployments (not just unit tests).
Surfaces as: pydantic_core._pydantic_core.ValidationError: 1 validation error for function-wrap[wrap_val()]

Proof / Evidence

GitHub issue: #10968
Fix PR: https://github.com/pydantic/pydantic/pull/11027
First fixed release: 2.10.3
Reproduced locally: No (not executed)
Last verified: 2026-02-09
Confidence: 0.85
Did this fix it?: Yes (upstream fix exists)
Own content ratio: 0.49

Discussion

High-signal excerpts from the issue thread (symptoms, repros, edge-cases).

Jump to Sources Open on GitHub

“AnyUrl doesn't allow localhost as host in v2.10.2: file://localhost/dir/file.suffix should be valid though, right?”

@kraftto · 2024-11-28 · source

“Hi! I believe this is better behavior - AnyUrl documentation suggested (even in v2.9.2) that a host was required, and now that is enforced. Let…”

@sydney-runkle · 2024-11-25 · source

“Alright, we'll fix this for v2.10.2. Thanks for bringing this to our attention!”

@sydney-runkle · 2024-11-25 · source

Failure Signature (Search String)

pydantic_core._pydantic_core.ValidationError: 1 validation error for function-wrap[wrap_val()]

Error Message

Stack trace

error.txt

Error Message
-------------
pydantic_core._pydantic_core.ValidationError: 1 validation error for function-wrap[wrap_val()]
  Input should be a valid URL, empty host [type=url_parsing, input_value='data:image/png;base64,iV...Y4OHwAAAABJRU5ErkJggg==', input_type=str]

Minimal Reproduction

repro.py

pydantic version: 2.10.1
        pydantic-core version: 2.27.1
          pydantic-core build: profile=release pgo=false
                 install path: /private/tmp/pyd/venv/lib/python3.12/site-packages/pydantic
               python version: 3.12.7 (main, Oct  1 2024, 02:05:46) [Clang 15.0.0 (clang-1500.3.9.4)]
                     platform: macOS-15.1-arm64-arm-64bit
             related packages: pydantic-settings-2.6.1 typing_extensions-4.12.2
                       commit: unknown

Environment

Python: 3.12
Pydantic: 2

Fix Options (Details)

Option A — Upgrade to fixed release Safe default (recommended)

pip install pydantic==2.10.3

When NOT to use: Do not use this fix if you require strict host validation for URLs.

Use when you can deploy the upstream fix. It is usually lower-risk than long-lived workarounds.

Fix reference: https://github.com/pydantic/pydantic/pull/11027

First fixed release: 2.10.3

Last verified: 2026-02-09. Validate in your environment.

When NOT to Use This Fix

Do not use this fix if you require strict host validation for URLs.

Verify Fix

verify

Re-run the minimal reproduction on your broken version, then apply the fix and re-run.

Did This Fix Work in Your Case?

Quick signal helps us prioritize which fixes to verify and improve.

Prevention

Add a CI check that diffs key outputs after upgrades (OpenAPI schema snapshots, JSON payload shapes, CLI output).
Upgrade behind a canary and run integration tests against the canary before 100% rollout.

Version Compatibility Table

Version	Status
2.10.3	Fixed

Related Issues

No related fixes found.

Cluster: pydantic:configuration-error Pydantic hub Pydantic best practices All hubs All clusters

Related clusters: Data consistency OpenAPI schema Serialization

Sources

We don’t republish the full GitHub discussion text. Use the links above for context.