CVE-2026-19879

A flaw was found in Undertow, an HTTP server, within its HTTP response header writing path. The writeString method performs a silent narrowing cast from 16-bit Unicode characters to 8-bit bytes when writing HTTP response header values. A remote attacker can exploit this by supplying specific...

CVE-2026-19879

Undertow contains a vulnerability in the HTTP response header writing path: the writeString() method narrows 16‑bit Unicode to 8‑bit bytes when writing header values, which can truncate characters to ASCII control/symbols and cause limited integrity impact or information disclosure if input isn’t...

CVE-2026-19879

A flaw was found in Undertow, an HTTP server, within its HTTP response header writing path. The writeString method performs a silent narrowing cast from 16-bit Unicode characters to 8-bit bytes when writing HTTP response header values. A remote attacker can exploit this by supplying specific...

PT-2026-72036

A flaw was found in Undertow, an HTTP server, within its HTTP response header writing path. The writeString method performs a silent narrowing cast from 16-bit Unicode characters to 8-bit bytes when writing HTTP response header values. A remote attacker can exploit this by supplying specific...