Vulnerability · Published May 12, 2026 · Assigned by apache
CVE-2026-42498Apache Tomcat: WebSocket authentication header exposure
High 7.3
In plain English
A high-severity information exposure in Apache Tomcat from Apache Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.7%top 47.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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-M1 through 11.0.21, from 10.1.0-M1 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | tomcat | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-admin-webapps | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-admin-webapps | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-admin-webapps | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-docs-webapp | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-docs-webapp | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-docs-webapp | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:8 | tomcat-el-3.0-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-el-3.0-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-el-5.0-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-jsp-2.3-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-jsp-2.3-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-jsp-3.1-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:10 | tomcat-lib | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-lib | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-lib | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:8 | tomcat-servlet-4.0-api | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-servlet-4.0-api | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat-servlet-6.0-api | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:10 | tomcat-webapps | 1:10.1.49-4.el10_2.alma.1 | ALSA-2026:69259 |
| AlmaLinux:8 | tomcat-webapps | 1:9.0.120-1.el8_10 | ALSA-2026:68677 |
| AlmaLinux:9 | tomcat-webapps | 1:9.0.120-2.el9_8 | ALSA-2026:68660 |
| AlmaLinux:10 | tomcat9 | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-admin-webapps | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-docs-webapp | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-el-3.0-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-jsp-2.3-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-lib | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-servlet-4.0-api | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| AlmaLinux:10 | tomcat9-webapps | 1:9.0.120-1.el10_2.alma.1 | ALSA-2026:68651 |
| Debian:12 | tomcat10 | 10.1.55-1~deb12u1 | DEBIAN-CVE-2026-42498 |
| Debian:13 | tomcat10 | 10.1.55-1~deb13u1 | DEBIAN-CVE-2026-42498 |
| Debian:14 | tomcat10 | 10.1.55-1 | DEBIAN-CVE-2026-42498 |
| Debian:13 | tomcat11 | 11.0.22-1~deb13u1 | DEBIAN-CVE-2026-42498 |
| Debian:14 | tomcat11 | 11.0.22-1 | DEBIAN-CVE-2026-42498 |
| Debian:12 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-42498 |
| Debian:13 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-42498 |
| Debian:14 | tomcat9 | 9.0.70-2 | DEBIAN-CVE-2026-42498 |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 10.1.55 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 11.0.22 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat.embed:tomcat-embed-core | 9.0.118 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat | 11.0.22 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat | 9.0.118 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat | 10.1.55 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat-catalina | 11.0.22 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat-catalina | 10.1.55 | GHSA-fv25-8xcx-gqjc |
| Maven | org.apache.tomcat:tomcat-catalina | 9.0.118 | GHSA-fv25-8xcx-gqjc |
| Rocky Linux:10 | tomcat | 1:10.1.49-4.el10_2 | RLSA-2026:69259 |
| Rocky Linux:8 | tomcat | 1:9.0.120-1.el8_10 | RLSA-2026:68677 |
| Rocky Linux:9 | tomcat | 1:9.0.120-2.el9_8 | RLSA-2026:68660 |
| Rocky Linux:10 | tomcat9 | 1:9.0.120-1.el10_2 | RLSA-2026:68651 |
| Ubuntu:25.10 | tomcat10 | 10.1.40-1ubuntu1.25.10.1 | UBUNTU-CVE-2026-42498 |
| Ubuntu:26.04:LTS | tomcat10 | 10.1.40-1ubuntu1.26.04.1 | UBUNTU-CVE-2026-42498 |
| Ubuntu:25.10 | tomcat11 | no fix listed | UBUNTU-CVE-2026-42498 |
| Ubuntu:25.10 | tomcat9 | 9.0.95-1ubuntu1.1 | UBUNTU-CVE-2026-42498 |
| Ubuntu:26.04:LTS | tomcat9 | 9.0.115-1ubuntu0.1 | UBUNTU-CVE-2026-42498 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Tomcat | 11.0.0-M1 – through 11.0.2110.1.0-M1 – through 10.1.549.0.2 – through 9.0.1178.5.24 – through 8.5.1007.0.83 – through 7.0.109 |
Weakness: CWE-200 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L