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Full vulnerability report · 2026
CVE-2026-42498High confidence

Apache Tomcat: WebSocket authentication header exposure

Apache Software Foundation · Apache Tomcat

7.3HighCVSS 3.1
Recommended action
Within 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

2 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · esm-appstomcat10Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.10.1.16-1ubuntu0.1~esm4Canonical record ↗Source updated 9 Sept 2026
Ubuntu 24.04 LTSnoble · esm-appstomcat9Vendor fix publishedCanonical reports that a fixed source package version has been published. Repository candidate availability is not checked by BlackTree.9.0.70-2ubuntu0.1+esm3Canonical record ↗Source updated 9 Sept 2026
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2026-42498 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitytomcat-coyote: Apache Tomcat: Information disclosure due to HTTP Authentication Header exposure during WebSocket authentication.
81 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • redhat-pki:10/jss.src as a component of Red Hat Certificate System 10
  • idm-jss as a component of Red Hat Enterprise Linux 10
  • idm-jss-tomcat as a component of Red Hat Enterprise Linux 10
  • mod_proxy_cluster as a component of Red Hat Enterprise Linux 10
  • mod_proxy_cluster.src as a component of Red Hat Enterprise Linux 10
  • tomcat as a component of Red Hat Enterprise Linux 10
  • tomcat-admin-webapps as a component of Red Hat Enterprise Linux 10
  • tomcat-docs-webapp as a component of Red Hat Enterprise Linux 10
  • tomcat-el-5.0-api as a component of Red Hat Enterprise Linux 10
  • tomcat-jsp-3.1-api as a component of Red Hat Enterprise Linux 10
  • tomcat-lib as a component of Red Hat Enterprise Linux 10
  • tomcat-servlet-6.0-api as a component of Red Hat Enterprise Linux 10
Summary
A flaw was found in Apache Tomcat. During WebSocket authentication, the HTTP Authentication Header can be exposed to unexpected hosts. This vulnerability leads to information disclosure, potentially allowing an attacker to gain access to sensitive authentication credentials.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-29515

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High technical severity; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Exposure of Sensitive Information to an Unauthorized Actor → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-200 ↗

CWE-200: Exposure of Sensitive Information to an Unauthorized Actor. The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CLowConfidentiality impact: A successful attack can cause a limited loss.ILowIntegrity impact: A successful attack can cause a limited loss.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-200
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-W-2026-2455Oracle Solaris Drittanbieterkomponenten: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in verschiedenen Komponenten von Drittanbietern in Oracle Solaris ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.

Official advisory
BSI · German · WID-SEC-W-2026-1955Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Atlassian Bamboo, Bitbucket, Confluence, Fisheye, Crucible, Jira und Jira Service Management ausnutzen, um beliebigen Code auszuführen, erweiterte Berechtigungen zu erlangen, Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren, vertrauliche Informationen offenzulegen oder einen Denial-of-Service-Zustand auszulösen.

Official advisory
BSI · German · WID-SEC-W-2026-1514Apache Tomcat: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Apache Tomcat ausnutzen, um Sicherheitsmaßnahmen zu umgehen, vertrauliche Informationen offenzulegen, Daten zu manipulieren, einen Denial-of-Service-Zustand herbeizuführen oder andere, nicht spezifizierte bezeichnete Angriffe durchzuführen.

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0986Multiples vulnérabilités dans les produits IBM

ord?id=CVE-2026-39979 Référence CVE CVE-2026-40164 https://www.cve.org/CVERecord?id=CVE-2026-40164 Référence CVE CVE-2026-4046 https://www.cve.org/CVERecord?id=CVE-2026-4046 Référence CVE CVE-2026-41254 https://www.cve.org/CVERecord?id=CVE-2026-41254 Référence CVE CVE-2026-41284 https://www.cve.org/CVERecord?id=CVE-2026-41284 Référence CVE CVE-2026-41293 https://www.cve.org/CVERecord?id=CVE-2026-41293 Référence CVE CVE-2026-41417 https://www.cve.org/CVERecord?id=CVE-2026-41417 Référence CVE CVE-2026-42496 https://www.cve.org/CVERecord?id=CVE-2026-42496 Référence CVE CVE-2026-42497 https://www.cve.org/CVERecord?id=CVE-2026-42497 Référence CVE CVE-2026-42498 https://www.cve.org/CVERecord?id=CVE-2026-42498 Référence CVE CVE-2026-42580 https://www.cve.org/CVERecord?id=CVE-2026-42580 Référence CVE CVE-2026-42581 https://www.cve.org/CVERecord?id=CVE-2026-42581 Référence CVE CVE-2026-42583 https://www.cve.org/CVERecord?id=CVE-2026-42583 Référence CVE CVE-2026-42584 https://www.cve.org/CVERecord?id=CVE-2026-42584 Référence CVE CVE-2026-42585 https://www.cve.org/CVERecord?id=CVE-2026-42585 Référence CVE CVE-2026-42587 https://www.cve.org/CVERecord?id=CVE-2026-42587 Référence CVE CVE-2026-42944 https://www.cve.org/CVERecord?id=CVE-2026-42944 Référence CVE CVE-2026-42959 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0773Multiples vulnérabilités dans les produits Atlassian

d?id=CVE-2026-41284 Référence CVE CVE-2026-41293 https://www.cve.org/CVERecord?id=CVE-2026-41293 Référence CVE CVE-2026-42033 https://www.cve.org/CVERecord?id=CVE-2026-42033 Référence CVE CVE-2026-42035 https://www.cve.org/CVERecord?id=CVE-2026-42035 Référence CVE CVE-2026-42038 https://www.cve.org/CVERecord?id=CVE-2026-42038 Référence CVE CVE-2026-42043 https://www.cve.org/CVERecord?id=CVE-2026-42043 Référence CVE CVE-2026-42211 https://www.cve.org/CVERecord?id=CVE-2026-42211 Référence CVE CVE-2026-42264 https://www.cve.org/CVERecord?id=CVE-2026-42264 Référence CVE CVE-2026-42342 https://www.cve.org/CVERecord?id=CVE-2026-42342 Référence CVE CVE-2026-42498 https://www.cve.org/CVERecord?id=CVE-2026-42498 Référence CVE CVE-2026-42579 https://www.cve.org/CVERecord?id=CVE-2026-42579 Référence CVE CVE-2026-42583 https://www.cve.org/CVERecord?id=CVE-2026-42583 Référence CVE CVE-2026-42584 https://www.cve.org/CVERecord?id=CVE-2026-42584 Référence CVE CVE-2026-42585 https://www.cve.org/CVERecord?id=CVE-2026-42585 Référence CVE CVE-2026-42587 https://www.cve.org/CVERecord?id=CVE-2026-42587 Référence CVE CVE-2026-43512 https://www.cve.org/CVERecord?id=CVE-2026-43512 Référence CVE CVE-2026-43513 https://www.cve.org/CVERecord?id=CVE-2026-43513 Référence CVE CVE-2026-43515 https://www.cve.org/CVERecord?id=

Official advisory
CERT-FR · French · CERTFR-2026-AVI-0577Multiples vulnérabilités dans Apache Tomcat

De multiples vulnérabilités ont été découvertes dans Apache Tomcat. Elles permettent à un attaquant de provoquer une atteinte à la confidentialité des données, un contournement de la politique de sécurité et un problème de sécurité non spécifié par l'éditeur.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
redhat-pki:10/jss.src as a component of Red Hat Certificate System 10; idm-jss as a component of Red Hat Enterprise Linux 10; idm-jss-tomcat as a component of Red Hat Enterprise Linux 10; mod_proxy_cluster as a component of Red Hat Enterprise Linux 10; mod_proxy_cluster.src as a component of Red Hat Enterprise Linux 10; tomcat as a component of Red Hat Enterprise Linux 10; tomcat-admin-webapps as a component of Red Hat Enterprise Linux 10; tomcat-docs-webapp as a component of Red Hat Enterprise Linux 10; tomcat-el-5.0-api as a component of Red Hat Enterprise Linux 10; tomcat-jsp-3.1-api as a component of Red Hat Enterprise Linux 10; tomcat-lib as a component of Red Hat Enterprise Linux 10; tomcat-servlet-6.0-api as a component of Red Hat Enterprise Linux 10; tomcat-webapps as a component of Red Hat Enterprise Linux 10; tomcat.src as a component of Red Hat Enterprise Linux 10; tomcat9 as a component of Red Hat Enterprise Linux 10; tomcat9-admin-webapps as a component of Red Hat Enterprise Linux 10; tomcat9-docs-webapp as a component of Red Hat Enterprise Linux 10; tomcat9-el-3.0-api as a component of Red Hat Enterprise Linux 10; tomcat9-jsp-2.3-api as a component of Red Hat Enterprise Linux 10; tomcat9-lib as a component of Red Hat Enterprise Linux 10; tomcat9-servlet-4.0-api as a component of Red Hat Enterprise Linux 10; tomcat9-webapps as a component of Red Hat Enterprise Linux 10; tomcat9.src as a component of Red Hat Enterprise Linux 10; tomcat6 as a component of Red Hat Enterprise Linux 6; tomcat6-admin-webapps as a component of Red Hat Enterprise Linux 6; tomcat6-docs-webapp as a component of Red Hat Enterprise Linux 6; tomcat6-el-2.1-api as a component of Red Hat Enterprise Linux 6; tomcat6-javadoc as a component of Red Hat Enterprise Linux 6; tomcat6-jsp-2.1-api as a component of Red Hat Enterprise Linux 6; tomcat6-lib as a component of Red Hat Enterprise Linux 6; and 51 more
Fixed
jws6-tomcat-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-0:10.1.49-15.redhat_00013.1.el10jws.src as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-admin-webapps-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-docs-webapp-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-el-5.0-api-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-javadoc-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-jsp-3.1-api-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-lib-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-selinux-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-servlet-6.0-api-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws6-tomcat-webapps-0:10.1.49-15.redhat_00013.1.el10jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 10; jws7-tomcat-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-0:11.0.21-5.redhat_00004.1.el10jws.src as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-admin-webapps-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-docs-webapp-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-el-5.0-api-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-javadoc-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-jsp-3.1-api-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-lib-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-selinux-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-servlet-6.0-api-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws7-tomcat-webapps-0:11.0.21-5.redhat_00004.1.el10jws.noarch as a component of Red Hat JBoss Web Server 7.0 on RHEL 10; jws6-tomcat-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-0:10.1.49-15.redhat_00013.1.el8jws.src as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-admin-webapps-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-docs-webapp-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-el-5.0-api-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-javadoc-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-jsp-3.1-api-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; jws6-tomcat-lib-0:10.1.49-15.redhat_00013.1.el8jws.noarch as a component of Red Hat JBoss Web Server 6.2 on RHEL 8; and 42 more
Action
Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 12 May 2026 · Last source change 13 May 2026, 15:59 UTC · CWE-200 · Exposure of Sensitive Information to an Unauthorized Actor

CVE recordCVE.org · 5.2
CVSS sourceCISA ADP
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2026-29515
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2026-29515↗Vendor CSAF · Red Hat Product Security↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-42498 · cve.blacktree.nl