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Full vulnerability report · 2026
CVE-2026-55956High confidence

Apache Tomcat: Security constraints for default servlet ignored method

Apache Software Foundation · Apache Tomcat

6.5MediumCVSS 3.1
Recommended action
Patch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 0.69% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Apache Software Foundation Apache Tomcat and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: As exposure requiresRemediation target: Within 365 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Cross-source reconciliation

Remediation availability differs by product scope

Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Distribution package intelligence

Release-specific package status

Debian, ubuntu findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

13 package states
Package result overrides the generic status

BlackTree has verified remediation for at least one product or source, but the relevant distribution still reports no fixed package for 3 affected package states shown here. Treat those rows as affected with no fix until that distribution publishes a fixed version.

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.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcetomcat10Affected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian trixietrixie · sourcetomcat11Affected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian trixietrixie · sourcetomcat9Vendor fix publishedDebian records a fixed source-package version for this release.9.0.70-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcetomcat10Affected, no fix publishedDebian currently tracks this release as open.Not published in this feedDebian Security Tracker ↗Source updated 6 Oct 2026
Debian bookwormbookworm · sourcetomcat9Vendor fix publishedDebian records a fixed source-package version for this release.9.0.70-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcetomcat10Vendor fix publishedDebian records a fixed source-package version for this release.10.1.60-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcetomcat11Vendor fix publishedDebian records a fixed source-package version for this release.11.0.24-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian forkyforky · sourcetomcat9Vendor fix publishedDebian records a fixed source-package version for this release.9.0.70-2Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcetomcat10Vendor fix publishedDebian records a fixed source-package version for this release.10.1.60-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcetomcat11Vendor fix publishedDebian records a fixed source-package version for this release.11.0.24-1Debian Security Tracker ↗Source updated 6 Oct 2026
Debian sidsid · sourcetomcat9Vendor fix publishedDebian records a fixed source-package version for this release.9.0.70-2Debian Security Tracker ↗Source updated 6 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appstomcat10Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 2026
Ubuntu 24.04 LTSnoble · esm-appstomcat9Under evaluationCanonical reports that the package might be affected and still needs evaluation or fixing.Not published in this feedCanonical Ubuntu Security ↗Source updated 5 Oct 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.

2 current
CVE-2026-55956 · CSAF 2.0 · revision 8 · interimSUSE Product Security TeamCVE-2026-55956
324 known affected

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

  • tomcat as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-admin-webapps as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-docs-webapp as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-el-3_0-api as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-javadoc as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-jsp-2_3-api as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-lib as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-servlet-4_0-api as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat-webapps as component of SUSE Linux Enterprise High Performance Computing 12 SP4
  • tomcat as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • tomcat-admin-webapps as component of SUSE Linux Enterprise High Performance Computing 12 SP5
  • tomcat-docs-webapp as component of SUSE Linux Enterprise High Performance Computing 12 SP5
Summary
Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.
Remediation
To install this SUSE Security Update use the SUSE recommended installation methods like YaST online_update or "zypper patch".
CVE-2026-55956 · CSAF 2.0 · revision 3 · finalRed Hat Product Securitytomcat: Apache Tomcat: Improper Authorization Allows Security Constraint Bypass
51 known affected

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

  • 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
  • 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
Summary
A flaw was found in Apache Tomcat where access control rules for the default servlet are improperly handled. An attacker can exploit this issue to bypass specific HTTP method restrictions, potentially gaining unauthorized access to protected application resources.
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.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

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-2026-40232

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 actionPatch only the product branches with a verified fix

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority. Verified remediation exists for at least one product or source, but 3 structured product or package states remain unresolved. Apply remediation only to the exact product branch confirmed by its source.

Fix availability varies by product
01

What, why and how

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

What

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

Why

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

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

Improper Authorization vulnerability in Apache Tomcat leads to security constraints specified for the default servlet ignoring any method or method omission configured as part of the constraint. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.22, from 10.1.0-M1 through 10.1.55, from 9.0.0.M1 through 9.0.118, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Other versions that have reached end of support may also be affected. Users are recommended to upgrade to version 11.0.23, 10.1.56 or 9.0.119, which fix the issue.

Why

The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

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 → Improper Authorization → 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-285 ↗

CWE-285: Improper Authorization. The product does not perform or incorrectly performs an authorization check when an actor attempts to access a resource or perform an action.

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:N

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.ANoneAvailability impact: No direct loss is represented by this metric.
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-285
A

Official authority intelligence

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

BSI · German · WID-SEC-2026-3401Oracle Siebel CRM: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Siebel CRM ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

Official advisory ↗
BSI · German · WID-SEC-2026-3043IBM QRadar SIEM: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in IBM QRadar SIEM ausnutzen, um Sicherheitsvorkehrungen zu umgehen, um seine Privilegien zu erhöhen, um einen Denial of Service Angriff durchzuführen, um Informationen offenzulegen, um Dateien zu manipulieren, um einen Cross-Site Scripting Angriff durchzuführen und um beliebigen Programmcode auszuführen.

Official advisory ↗
BSI · German · WID-SEC-2026-2887Oracle Communications: Mehrere Schwachstellen

Ein entfernter, anonymer oder authentisierter Angreifer kann mehrere Schwachstellen in Oracle Communications ausnutzen, um die Vertraulichkeit, Integrität und Verfügbarkeit zu gefährden.

Official advisory ↗
BSI · German · WID-SEC-2026-2123Apache Tomcat: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Apache Tomcat ausnutzen, um Sicherheitsmaßnahmen zu umgehen, einen Denial-of-Service-Zustand zu verursachen, Cross-Site-Scripting-Angriffe durchzuführen oder andere, nicht näher spezifizierte Auswirkungen auszulösen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20260701Security Bulletin 1 July 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 1 July 2026, published on 1 July 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-1094Multiples vulnérabilités dans les produits IBM

d?id=CVE-2026-55276 Référence CVE CVE-2026-55379 https://www.cve.org/CVERecord?id=CVE-2026-55379 Référence CVE CVE-2026-55380 https://www.cve.org/CVERecord?id=CVE-2026-55380 Référence CVE CVE-2026-55443 https://www.cve.org/CVERecord?id=CVE-2026-55443 Référence CVE CVE-2026-55653 https://www.cve.org/CVERecord?id=CVE-2026-55653 Référence CVE CVE-2026-55655 https://www.cve.org/CVERecord?id=CVE-2026-55655 Référence CVE CVE-2026-55693 https://www.cve.org/CVERecord?id=CVE-2026-55693 Référence CVE CVE-2026-55798 https://www.cve.org/CVERecord?id=CVE-2026-55798 Référence CVE CVE-2026-55955 https://www.cve.org/CVERecord?id=CVE-2026-55955 Référence CVE CVE-2026-55956 https://www.cve.org/CVERecord?id=CVE-2026-55956 Référence CVE CVE-2026-56852 https://www.cve.org/CVERecord?id=CVE-2026-56852 Référence CVE CVE-2026-57455 https://www.cve.org/CVERecord?id=CVE-2026-57455 Référence CVE CVE-2026-57456 https://www.cve.org/CVERecord?id=CVE-2026-57456 Référence CVE CVE-2026-57819 https://www.cve.org/CVERecord?id=CVE-2026-57819 Référence CVE CVE-2026-58016 https://www.cve.org/CVERecord?id=CVE-2026-58016 Référence CVE CVE-2026-59083 https://www.cve.org/CVERecord?id=CVE-2026-59083 Référence CVE CVE-2026-59084 https://www.cve.org/CVERecord?id=CVE-2026-59084 Référence CVE CVE-2026-59197 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2026-AVI-0817Multiples vulnérabilités dans Apache Tomcat

De multiples vulnérabilités ont été découvertes dans Apache Tomcat. Certaines d'entre elles permettent à un attaquant de provoquer une injection de code indirecte à distance (XSS), un contournement de la politique de sécurité et un problème de sécurité non spécifié par l'éditeur.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2026-021994Apache Tomcatにおける複数の脆弱性（2026年6月29日）

The Apache Software Foundationから、Apache Tomcatの脆弱性（CVE-2026-55957, CVE-2026-55956, CVE-2026-55955, CVE-2026-55276, CVE-2026-53434, CVE-2026-53404, CVE-2026-50229）に対してアドバイザリが公開されました。 Fixed in Apache Tomcat 11.0.23 Fixed in Apache Tomcat 11.0.5 Fixed in Apache Tomcat 10.1.56 Fixed in Apache Tomcat 10.1.39 Fixed in Apache Tomcat 9.0.119 Fixed in Apache Tomcat 9.0.102

Official advisory ↗
NCSC-NL · Dutch · NCSC-2026-0309Kwetsbaarheden verholpen in Oracle Communications

Multiple Apache Tomcat versions contain an improper authorization vulnerability in the default servlet that bypasses HTTP method restrictions, fixed in versions 11.0.23, 10.1.56, and 9.0.119, alongside other security and bug fixes.

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.
Fix availability varies by product
Affected
Fixed
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
Action
Use the product-specific evidence above. Patch only products with a verified fixed release, and keep every affected or under-investigation state without a matching fix in the remediation queue.
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 29 Jun 2026 · Last source change 30 Jun 2026, 13:25 UTC · CWE-285 · Improper Authorization

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-2026-40232
Product sourceVendor CSAF · SUSE Product Security Team
Remediation sourceVendor CSAF · SUSE Product Security Team
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 ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    11.0.0-M1 ≤ 11.0.22; 10.1.0-M1 ≤ 10.1.55; 9.0.0.M1 ≤ 9.0.118; 8.5.0 ≤ 8.5.100; 7.0.0 ≤ 7.0.109; < 7.0.0 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    11.0.0-M1 ≤ 11.0.22; 10.1.0-M1 ≤ 10.1.55; 9.0.0.M1 ≤ 9.0.118; 8.5.0 ≤ 8.5.100; 7.0.0 ≤ 7.0.109; < 7.0.0 · Fixed: 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
    Red Hat Product Security ↗
  2. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    Red Hat Product Security ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2026-40232↗Vendor CSAF · SUSE Product Security Team↗Red Hat Product Security security advisory↗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-2026-55956 · cve.blacktree.nl