UUID4 validation from string not strict enough

[hassec]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

The string representation of "00000000-0000-4000-0000-000000000000", is not a valid UUID because the first digit of the fourth group would have to be one of [8,9,a,b].

See attached example, I think that both instantiations of A(..) should throw a validation error.

Example Code

from pydantic import BaseModel, UUID4
import uuid

class A(BaseModel):
    x: UUID4


not_u4_str = "00000000-0000-4000-0000-000000000000"
not_u4 = uuid.UUID(not_u4_str)
print(not_u4.version)
A(x=not_u4_str)
A(x=UUID('00000000-0000-4000-0000-000000000000'))

Python, Pydantic & OS Version

pydantic version: 2.5.3
        pydantic-core version: 2.14.6
          pydantic-core build: profile=release pgo=true
                 install path: /Users/chasse/software/pyenv/versions/3.10.13...
               python version: 3.10.13 (main, Sep 10 2023, 20:18:32) [Clang 14.0.3 (clang-1403.0.22.14.1)]
                     platform: macOS-14.2.1-arm64-arm-64bit
             related packages: typing_extensions-4.9.0

[sydney-runkle]

@hassec,

Thanks for reporting this. This does seem like a bug, but one for pydantic-core. Moving it there now 👍