Netty is an asynchronous, event-driven network application framework. In versions prior to 4.1.136.Final and 4.2.16.Final, Netty's STOMP encoder ( StompSubframeEncoder ) does not escape or validate header values in CONNECT and CONNECTED frames, so raw newline ( \n ) characters in a header value are written directly to the wire, allowing an attacker who controls a header value to inject additional STOMP headers. This happens because the encoder intentionally skips escaping for CONNECT/CONNECTED frames per the STOMP 1.2 specification but never rejects the raw newlines, and since a broker parses each line as a separate header, an attacker controlling a value such as a user-supplied login or passcode can overwrite connection parameters or add authentication/role headers to bypass authentication or escalate privileges (the actual impact is broker-dependent). The issue is fixed in versions 4.1.136.Final and 4.2.16.Final.
{
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59920.json",
"cwe_ids": [
"CWE-93"
]
}{
"source": "CPE_RANGE",
"extracted_events": [
{
"introduced": "0"
},
{
"fixed": "4.1.136"
},
{
"introduced": "4.2.0"
},
{
"fixed": "4.2.16"
}
],
"cpe": "cpe:2.3:a:netty:netty:*:*:*:*:*:*:*:*"
}