[cogman10]

Other answers are good. One more that you could do is put the JSON document inside a container (A zip archive for example). Then your document can effectively be

    invoice.inv (zip archive)
    └- payload.json
    └- signature.asc

This has the benefit of adding more opportunities for many json documents within the archive.

It's effectively what the Java jar is.

[bsamuels]

dont unzip an untrusted payload

[cogman10]

Unless you are worried about something like a gzip bomb, I don't see why this is an issue. A lot of formats are effectively just zips. The xlsx, odf, etc for example. It's a pretty common format style.

It helps to have a well defined expected structure in the archive.

[boston_clone]

hello,

https://nvd.nist.gov/vuln/detail/CVE-2025-11001

[cogman10]

Right, so long as step 1 in reading your file isn't "extract everything" you're pretty safe.

This specific exploit is one that only exists when you are extracting a zip on windows.

[boston_clone]

this is just one instance of a vulnerability associated with unzipping; a curious search would yield more.

[cogman10]

A curious search reveals that vulnerabilities that do exist are of 2 flavors.

1. Standard C memory vulnerabilities

2. Unsafe file traversal while unzipping

The entire second class is avoided in a fixed file format. The first class of vulnerabilities plague everything. A quick look at libxml2 CVEs shows that.