CVE-2026-19879 - Io.undertow/undertow: undertow: http response header integrity issue due to character truncation
Brief
CVE ID : CVE-2026-19879
Published : Aug. 14, 2026, 2:51 p. m.
- 14 minutes ago
Description : 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.
Severity: 5.3
- MEDIUM
Visit the link for more details, such as CVSS details, affected products, timeline, and more...