CVE-2026-42498

Description

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0 through 11.0.21, from 10.1.0 through 10.1.54, from 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118, which fix the issue.

How to fix CVE-2026-42498

To remediate CVE-2026-42498, upgrade the affected package to a fixed version below.

—upgrade to 10.1.55 or later
—upgrade to 10.1.55-1~deb12u1 or later
—upgrade to 11.0.22-1~deb13u1 or later
—upgrade to 9.0.118-0+deb11u1 or later
—upgrade to 9.0.118 or later
—upgrade to 9.0.118 or later
—upgrade to 9.0.118 or later

Is CVE-2026-42498 being exploited?

Low — EPSS is 0.5%, meaning exploitation activity has not been observed at scale.

Affected packages (7)

>= 10.0.0, < 10.1.55, >= 11.0.0, < 11.0.22, >= 9.0.0, < 9.0.118
from 0, < 10.1.55-1~deb12u1
from 0, < 11.0.22-1~deb13u1
from 0, < 9.0.118-0+deb11u1
from 0, < 9.0.118
from 0, < 9.0.118
from 0, < 9.0.118

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	HIGH7.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L