---
id: 8487
title: "Parse and Parse: MIME Validation Bypass to XSS via Parser Differential"
source_domain: lab.ctbb.show
source_url: "https://lab.ctbb.show/research/parse-and-parse-mime-validation-bypass-to-xss-via-parser-differential"
published_at: "2026-01-30T00:00:00Z"
tags: ["web-security", "xss", "research", "mime", "content-type", "parser-differential", "header-validation", "browser-parsing"]
phying_url: "https://phying.com/item/8487"
lang: en
---

# Parse and Parse: MIME Validation Bypass to XSS via Parser Differential

## Summary

A researcher demonstrates how a single comma in the Content-Type header creates a parser differential between browsers and MIME parsing libraries, letting attackers bypass validation and achieve reflected XSS.

## Intelligence Metadata

- **Sources:** lab.ctbb.show
- **Published:** 2026-01-30T00:00:00Z
- **Original:** https://lab.ctbb.show/research/parse-and-parse-mime-validation-bypass-to-xss-via-parser-differential
- **Phying News:** https://phying.com/item/8487