Preliminary research
Parse and Parse: MIME Validation Bypass to XSS via Parser Differential
AI-collected research leads through 22 September 2026, including targeted additions between broader sweeps. Unranked, incomplete, not community-vetted, and subject to change.
Content-Type is a singleton field, but Chromium and Firefox coalesce it on commas and keep the last syntactically valid type, while MIME libraries split at the first semicolon and keep the first. So application/json;,text/html passes a server-side check as JSON yet renders as HTML despite nosniff; adding = satisfies parsers that demand a name-value parameter, and Chromium reading ( as a comment start hides it. 17 parsers are tabulated.
Record
- Researcher
- Tang Cheuk Hei
- Published by
- Critical Thinking - Bug Bounty Podcast
- Date
- Topic
- XSS
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This page is the archive's own catalogue record. The research is the work of Tang Cheuk Hei, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on .