CVE-2026-19879
No fix known EPSS <1%CVSS 5.3
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 Unicode characters in user-controlled input that an application places into response headers. This can lead to the truncation of these characters into ASCII control characters or special symbols, potentially resulting in limited integrity impact or information disclosure if the application does not properly sanitize user input.
Products: Red Hat build of Apache Camel for Spring Boot 4, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat JBoss Enterprise Application Platform 7, Red Hat JBoss Enterprise Application Platform 8, Red Hat JBoss Enterprise Application Platform Expansion Pack, Red Hat Single Sign-On 7
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Debian 14 | undertow | no fix |
| Ubuntu 26.04 LTS | undertow | no fix |
| Ubuntu 26.10 | undertow | no fix |
| Ubuntu Pro 16.04 LTS | undertow | no fix |
| Ubuntu Pro 18.04 LTS | undertow | no fix |
| Ubuntu Pro 20.04 LTS | undertow | no fix |
| Ubuntu Pro 22.04 LTS | undertow | no fix |
| Ubuntu Pro 24.04 LTS | undertow | no fix |