NVD

CVE-2026-19879 Detail

Received

This CVE record has recently been published to the CVE List and has been included within the NVD dataset.

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.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

CVSS 3.x Severity and Vector Strings:

Nist CVSS score does not match with CNA score

CNA: Red Hat, Inc.

Base Score: 5.3 MEDIUM

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

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URL	Source(s)	Tag(s)
https://access.redhat.com/security/cve/CVE-2026-19879	Red Hat, Inc.
https://bugzilla.redhat.com/show_bug.cgi?id=2516038	Red Hat, Inc.

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-681	Incorrect Conversion between Numeric Types	Red Hat, Inc.

Change History

1 change records found show changes

New CVE Received from Red Hat, Inc. 8/14/2026 11:17:09 AM

Action	Type	New Value
Added	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.
Added	CVSS V3.1	AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Added	CWE	CWE-681
Added	Reference	https://access.redhat.com/security/cve/CVE-2026-19879
Added	Reference	https://bugzilla.redhat.com/show_bug.cgi?id=2516038
Added	Affected	Record truncated, showing 2048 of 6630 characters. View Entire Change Record [{"vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-core","cpes":["cpe:/a:redhat:camel_spring_boot:4"]},{"vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-parent","cpes":["cpe:/a:redhat:camel_spring_boot:4"]},{"vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-servlet","cpes":["cpe:/a:redhat:camel_spring_boot:4"]},{"vendor":"Red Hat","product":"Red Hat build of Apache Camel for Spring Boot 4","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"undertow-websockets-jsr","cpes":["cpe:/a:redhat:camel_spring_boot:4"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 10","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"moditect","cpes":["cpe:/o:redhat:enterprise_linux:10"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"pki-core:10.6/resteasy","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 8","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"pki-deps:10.6/resteasy","cpes":["cpe:/o:redhat:enterprise_linux:8"]},{"vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","defaultStatus":"affected","collectionURL":"https://access.redhat.com/downloads/content/package-browser/","packageName":"resteasy","cpes":["cpe:/o:redhat:enterprise_linux:9"]},{"vendor":"Red

Quick Info

CVE Dictionary Entry:
CVE-2026-19879
NVD Published Date:
08/14/2026
NVD Last Modified:
08/14/2026
Source:
Red Hat, Inc.

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Information Technology Laboratory

National Vulnerability Database