5.1.0 accepts lessThan 0 (seen in inverted ranges)

[ElectricNroff]

There are four CVE Records with:

"lessThan":"0"

For all four, it seems that the lessThan value and the version value were swapped:

"cveId": "CVE-2021-28500" ...
"lessThan":"0","status":"affected","version":"4.20"

"cveId":"CVE-2022-4554" ...
"lessThan":"0","status":"affected","version":"1.0.0.347"

"cveId":"CVE-2023-5914" ...
"lessThan":"0","status":"affected","version":"2311 Current Release"

"cveId":"CVE-2023-6184" ...
"lessThan":"0","status":"affected","version":"2311 Current Release"

Negative version numbers are not normally seen, and thus "lessThan":"0" ranges are probably only used by accident.

This could be prevented by a schema that has a new definition such as versionButNotZero that is similar to:

cve-schema/schema/CVE_Record_Format.json

Lines 81 to 85 in 30f59c7

	"version": {
	"description": "A single version of a product, as expressed in its own version numbering scheme.",
	"type": "string",
	"minLength": 1,
	"maxLength": 1024

but with a negative lookahead:

"pattern": "^(?!0$)",

and use this for:

cve-schema/schema/CVE_Record_Format.json

Lines 320 to 327 in 30f59c7

	"lessThan": {
	"description": "The non-inclusive upper limit of the range. This is the least version NOT in the range. The usual version syntax is expanded to allow a pattern to end in an asterisk `(*)`, indicating an arbitrarily large number in the version ordering. For example, `{version: 1.0 lessThan: 1.*}` would describe the entire 1.X branch for most range kinds, and `{version: 2.0, lessThan: *}` describes all versions starting at 2.0, including 3.0, 5.1, and so on. Only one of lessThan and lessThanOrEqual should be specified.",
	"$ref": "#/definitions/version"
	},
	"lessThanOrEqual": {
	"description": "The inclusive upper limit of the range. This is the greatest version contained in the range. Only one of lessThan and lessThanOrEqual should be specified. For example, `{version: 1.0, lessThanOrEqual: 1.3}` covers all versions from 1.0 up to and including 1.3.",
	"$ref": "#/definitions/version"
	},

(but not for version where 0 is meaningful)