Address review feedback: keep the global express.json() at the default
100kb and mount a route-scoped 10mb parser in front of it for
/api/v1/monitors/import/json. Express matches middleware in registration
order, so the import route uses the larger parser and every other
endpoint keeps the tight default. No change in DoS surface for normal
traffic.
Express defaults to a 100kb JSON body, which is too small for realistic
imports through POST /api/v1/monitors/import/json (backups with many
monitors and their config easily exceed 100kb, returning
"request entity too large").
Raise the parser cap to 10mb. That covers real-world import payloads
while keeping the DoS surface bounded — a larger, streaming file-upload
route for imports remains desirable as a follow-up.
Detect custom domains by comparing the request host to the app host and apply
the tightened CSP there too, not just on the public path. Run the middleware
before express.static so static-served root documents get the header, and keep
helmet after static so its default-src does not block custom domain API calls.
Layer a stricter Content-Security-Policy on the /status/public document so
custom CSS cannot load external images, fonts, or stylesheets. Browsers
enforce the intersection of all CSP headers, so this only narrows the public
status page and never loosens the global policy, while keeping the app's
Google Fonts. Browser-enforced backstop behind the validator.
Replace the regex/escape-normalizer with @csstools/css-tokenizer (already
present transitively). Tokenizing resolves comments, hex escapes, and line
continuations into the real value before scanning, so obfuscated forms (a
scheme split by a line continuation or hex escape) cannot slip past. Scan
url-tokens and string-tokens to cover url(), quoted @import, and string-form
image functions. Add regression tests for the bypasses.
Reject status page custom CSS containing @import or a url() / image-set()
/ image() / cross-fade() whose target is http(s) or protocol-relative,
while allowing data: and relative URLs. The check normalizes comments and
CSS escapes first so obfuscated forms cannot slip past. Enforced in the
create/update body validation.
Alex Holliday
gorkem-bwl
Harshitbro-ctrlv
Arnaud GRIMBERT
Buco7854