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TI-2026-47098 Aliases CVE-2026-66299GHSA-rpf9-hrjr-88fv

Apache Tomcat: DoS via WebSocket chat example

Priority MEDIUM 40CWE-400Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Partial Red Hat: 6 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-400.

Summary

Uncontrolled Resource Consumption vulnerability in Apache Tomcat's WebSocket chat example. This issue affects Apache Tomcat: from 11.0.0-M20 through 11.0.24, from 10.1.24 through 10.1.57, from 9.0.89 through 9.0.120. Users who have followed the security guidance to remove the examples web application are not affected by this issue. Users are recommended to remove the examples web application or to upgrade to version 11.0.25, 10.1.58 or 9.0.121 (when released), which fix the issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00553 46th percentileScored 2026-11-07
Fix Partial Red Hat: 5 advisoriesRed Hat: 6 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
ApacheApache Tomcat11.0.0-M20 – 11.0.24; 10.1.24 – 10.1.57; 9.0.89 – 9.0.120—Patch availableCNA
  • Apache Tomcat VendorApache Affected 11.0.0-M20 – 11.0.24; 10.1.24 – 10.1.57; 9.0.89 – 9.0.120 Fixed in — Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*9.0.89 to before 9.0.121; 10.1.24 to before 10.1.58; 11.0.1 to before 11.0.25VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone20:*:*:*:*:*:*11.0.0 milestone20VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone21:*:*:*:*:*:*11.0.0 milestone21VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone22:*:*:*:*:*:*11.0.0 milestone22VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone23:*:*:*:*:*:*11.0.0 milestone23VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone24:*:*:*:*:*:*11.0.0 milestone24VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone25:*:*:*:*:*:*11.0.0 milestone25VulnerableApache
cpe:2.3:a:apache:tomcat:11.0.0:milestone26:*:*:*:*:*:*11.0.0 milestone26VulnerableApache
  • cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:* Versions 9.0.89 to before 9.0.121; 10.1.24 to before 10.1.58; 11.0.1 to before 11.0.25 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone20:*:*:*:*:*:* Versions 11.0.0 milestone20 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone21:*:*:*:*:*:* Versions 11.0.0 milestone21 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone22:*:*:*:*:*:* Versions 11.0.0 milestone22 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone23:*:*:*:*:*:* Versions 11.0.0 milestone23 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone24:*:*:*:*:*:* Versions 11.0.0 milestone24 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone25:*:*:*:*:*:* Versions 11.0.0 milestone25 Vulnerable ·Apache
  • cpe:2.3:a:apache:tomcat:11.0.0:milestone26:*:*:*:*:*:* Versions 11.0.0 milestone26 Vulnerable ·Apache

Remediation

Red Hat 5 advisories

  • RHSA-2026:76952 Released 2026-10-07 · Red Hat rating Important
    Red Hat JBoss Web Server 7.0.2 release and security update
    • Red Hat JBoss Web Server 7.0 on RHEL 10 jws7-tomcat-11.0.21-7.redhat_00006.1.el10jws, jws7-tomcat-admin-webapps-11.0.21-7.redhat_00006.1.el10jws, jws7-tomcat-docs-webapp-11.0.21-7.redhat_00006.1.el10jws +7
    • Red Hat JBoss Web Server 7.0 on RHEL 8 jws7-tomcat-11.0.21-7.redhat_00006.1.el8jws, jws7-tomcat-admin-webapps-11.0.21-7.redhat_00006.1.el8jws, jws7-tomcat-docs-webapp-11.0.21-7.redhat_00006.1.el8jws +7
    • Red Hat JBoss Web Server 7.0 on RHEL 9 jws7-tomcat-11.0.21-7.redhat_00006.1.el9jws, jws7-tomcat-admin-webapps-11.0.21-7.redhat_00006.1.el9jws, jws7-tomcat-docs-webapp-11.0.21-7.redhat_00006.1.el9jws +7
  • RHSA-2026:76956 Released 2026-10-07 · Red Hat rating Important
    Red Hat JBoss Web Server 7.0.2 release and security update
    • Red Hat JBoss Web Server 7.0.2
  • RHSA-2026:73981 Released 2026-10-01 · Red Hat rating Important
    Red Hat JBoss Web Server 6.2.5 release and security update
    • Red Hat JBoss Web Server 6.2 on RHEL 10 jws6-tomcat-10.1.49-16.redhat_00016.1.el10jws, jws6-tomcat-admin-webapps-10.1.49-16.redhat_00016.1.el10jws, jws6-tomcat-docs-webapp-10.1.49-16.redhat_00016.1.el10jws +7
    • Red Hat JBoss Web Server 6.2 on RHEL 8 jws6-tomcat-10.1.49-16.redhat_00016.1.el8jws, jws6-tomcat-admin-webapps-10.1.49-16.redhat_00016.1.el8jws, jws6-tomcat-docs-webapp-10.1.49-16.redhat_00016.1.el8jws +7
    • Red Hat JBoss Web Server 6.2 on RHEL 9 jws6-tomcat-10.1.49-16.redhat_00016.1.el9jws, jws6-tomcat-admin-webapps-10.1.49-16.redhat_00016.1.el9jws, jws6-tomcat-docs-webapp-10.1.49-16.redhat_00016.1.el9jws +7
Show 2 more Red Hat advisories
  • RHSA-2026:73982 Released 2026-10-01 · Red Hat rating Important
    Red Hat JBoss Web Server 6.2.5 release and security update
    • Red Hat JBoss Web Server 6.2.5
  • RHSA-2026:56039 Released 2026-08-18 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images tomcat11-1:11.0.25-0.1.hum1@noarch@public-hummingbird-aarch64-rpms, tomcat11-1:11.0.25-0.1.hum1@noarch@public-hummingbird-x86_64-rpms, tomcat11-1:11.0.25-0.1.hum1@src +18

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux 9AffectedNo fix yet
Red Hat Hardened ImagesFixed RHSA-2026:56039
Red Hat JBoss Web Server 6.2 on RHEL 10Fixed RHSA-2026:73981
Red Hat JBoss Web Server 6.2 on RHEL 8Fixed RHSA-2026:73981
Red Hat JBoss Web Server 6.2 on RHEL 9Fixed RHSA-2026:73981
Red Hat JBoss Web Server 6.2.5Fixed RHSA-2026:73982
Red Hat JBoss Web Server 7.0.2Fixed RHSA-2026:76956
Not affected: 7 products
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9
  • Red Hat Hardened Images
  • Red Hat JBoss Web Server 5
  • Red Hat JBoss Web Server 7

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-66299
  2. 2026-10-03 Alias added: GHSA-rpf9-hrjr-88fv
  3. 2026-10-07 Fix available: RHSA-2026:76952 · Red Hat
  4. 2026-10-07 Affected versions changed · Red Hat
  5. 2026-10-09 Fix available: RHSA-2026:76956 · Red Hat
  6. 2026-10-16 Fix available: Red Hat JBoss Web Server 7.0.2 · Red Hat

References

Advisory 2

  • TI-2025-18529 Apache Tomcat: Potential RCE and/or information disclosure and/or information corruption with partial PUT KEVCVSS 3.1CRITICAL 10.0
  • TI-2020-01862 Improper privilege management in Apache Tomcat KEVCVSS 3.1CRITICAL 9.8
  • TI-2016-07192 Improper access control in Apache Tomcat KEVCVSS 3.1CRITICAL 9.8
  • TI-2017-09342 Unrestricted file upload in Apache Tomcat KEVCVSS 3.1HIGH 8.1
  • TI-2017-09340 Unrestricted file upload in Apache Tomcat KEVCVSS 3.1HIGH 8.1
  • TI-2026-26741 Apache Tomcat: Fix for CVE-2026-29146 allowed bypass of EncryptInterceptor KEVCVSS 3.1HIGH 7.5
See all 273 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences