CVE-2021-43530

MEDIUM

Firefox for Android < 94.0 - Universal Cross-Site Scripting via QR Code URL Processing

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-43530. PoCs published by hfh86.

AI-analyzed exploit summary This repository contains a writeup and proof-of-concept for CVE-2021-43530, a Universal XSS vulnerability in Firefox for Android due to improper URL sanitization when processing QR codes. The vulnerability affects Firefox versions prior to 94.

Description

A Universal XSS vulnerability was present in Firefox for Android resulting from improper sanitization when processing a URL scanned from a QR code. *This bug only affects Firefox for Android. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94.

Exploits (1)

nomisec WRITEUP 1 stars
by hfh86 · poc
https://github.com/hfh86/CVE-2021-43530-UXSS-On-QRcode-Reader-

This repository contains a writeup and proof-of-concept for CVE-2021-43530, a Universal XSS vulnerability in Firefox for Android due to improper URL sanitization when processing QR codes. The vulnerability affects Firefox versions prior to 94.

Classification
Writeup 90%
Attack Type
Xss
Complexity
Trivial
Reliability
Reliable
Target: Firefox for Android < 94
No auth needed
Prerequisites: Firefox for Android < 94 · Ability to scan a malicious QR code
MITRE ATT&CK
mistral-large-3 · analyzed Feb 16, 2026 Full analysis →

References (2)

Core 2
Core References
Issue Tracking, Permissions Required x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1736886

Scores

CVSS v3 6.1
EPSS 0.0139
EPSS Percentile 69.2%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Details

CWE
CWE-79
Status published
Products (1)
mozilla/firefox < 94.0
Published Dec 08, 2021
Tracked Since Feb 18, 2026