Is MathML really Dangerous?

Dear W3C Math WG,

I wonder if there is a resilient security assessment for MathML. It
would be nice, if there was at least a subset of MathML, for which the
security was proven according to state-of-the-art of science and
technology. For example I could imagine that only presentation MathML
without a finite list of possible dangerous elements such as maction
or annotation could be the secure MathML subset.

The background of my question is that the Wikimedia Foundation
considers opening the POST endpoint for converting several input
formats (i.e. TeX, AsciMathML, and MathML) to MathML + SVG (+ PNG) [1]
for the public[2].
Currently this conversion endpoint it is only accessible from within
the Wikimedia Foundation cluster and only accepts texvc* input.

Best

Moritz Schubotz

[1] https://en.wikipedia.org/api/rest_v1/?doc#!/Math/post_media_math_check_=
type
if you try this link you=E2=80=99ll get a =E2=80=9CThis client is not allow=
ed to use
the endpoint=E2=80=9D exception rather than the security checked texvc outp=
ut
you receive in the unstable demo here
http://math.beta.wmflabs.org:7231/math.beta.wmflabs.org/v1/?doc#!/Math/post=
_media_math_check_type

[2] https://phabricator.wikimedia.org/T116147

*) texvc is a well-defined subset of LaTeX with some custom macros.