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Full vulnerability report · 2026
CVE-2026-56098High confidence

Rubygem-katello: improper authorization logic allows resource enumeration

Red Hat · Red Hat Satellite 6.16 for RHEL 8

Official source article: Red Hat RHSA-2026:74503 ↗. Check the applicable product and release in the original source.

4.3MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
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.
  • EPSS is 0.31% 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 Red Hat Red Hat Satellite 6.16 for RHEL 8 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.

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-2026-56098 · CSAF 2.0 · revision 3 · finalRed Hat Product Securityrubygem-katello: improper authorization logic allows resource enumeration
8 known affected

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

  • foreman-proxy-content as a component of Red Hat Satellite 6
  • katello as a component of Red Hat Satellite 6
  • katello-capsule as a component of Red Hat Satellite 6
  • katello-common as a component of Red Hat Satellite 6
  • katello-debug as a component of Red Hat Satellite 6
  • katello-service as a component of Red Hat Satellite 6
  • katello.src as a component of Red Hat Satellite 6
  • satellite:el8/rubygem-katello.src as a component of Red Hat Satellite 6
Summary
A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.
Remediation
Before applying this update, make sure all previously released errata relevant to your system have been applied. For detailed instructions how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_satellite/6.16/html/updating_red_hat_satellite/index Release Notes: Provisioning tokens are now required for all Operating System entries with Redhat family set. Attempts to download a unattended template without valid token will lead to “a provisioning token is required but a valid one was not provided” error. This changed behavior will lead to inability to use Generic or Subnet Bootdisks, systems using this bootdiks will be not matched with the host entry and not boot. To use Bootdisk after applying the errata, either use Full Host Bootdisk which uses tokens, or set Administer - Settings - Provisioning - Installation token lifetime to zero. This turns off the token enforcement and allows unauthenticated parties to use arbitrary MAC addresses in unattended requests to fetch provisioning kickstart with possibly sensitive data.
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-2026-90971

No EUVD known-exploited evidence

A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.

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
4.3 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.

What

A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.

Why

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.

Why

The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

How

An attacker operating through a network path may attempt exploitation with low privileges. 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 → Observable Discrepancy → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
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-203 ↗

CWE-203: Observable Discrepancy. The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor.

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:L/UI:N/S:U/C:L/I:N/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.PRLowPrivileges required: The attacker needs basic user-level 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.INoneIntegrity impact: No direct loss is represented by this metric.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.
NetworkCWE-203
A

Official authority intelligence

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

ENISA EUVD · EUVD-2026-90971Official EUVD mapping

A flaw was found in rubygem-katello. The RegistryProxiesController in Katello contains an authorization bypass vulnerability due to an execution fall-through in the registry_authorize filter. While the application identifies unauthorized requests and triggers an error response via the unauthorized method, it fails to halt the execution of the current code path (missing return statement). This failure in the control flow allows the application to proceed into subsequent business logic and database validation filters. Consequently, the application reveals its internal state through differential responses, allowing an unprivileged attacker to enumerate valid Users, Organizations, and Products across the entire instance.

Official EUVD record ↗
Cyber Security Agency of Singapore · English · CSA-SB-20261007Security Bulletin 7 Oct 2026

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 7 Oct 2026, published on 7 October 2026. Open the linked bulletin for the product, severity and reference information published in that issue.

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
Fixed
Action
Before applying this update, make sure all previously released errata relevant to your system have been applied. For detailed instructions how to apply this update, refer to: https://docs.redhat.com/en/documentation/red_hat_satellite/6.16/html/updating_red_hat_satellite/index Release Notes: Provisioning tokens are now required for all Operating System entries with Redhat family set. Attempts to download a unattended template without valid token will lead to “a provisioning token is required but a valid one was not provided” error. This changed behavior will lead to inability to use Generic or Subnet Bootdisks, systems using this bootdiks will be not matched with the host entry and not boot. To use Bootdisk after applying the errata, either use Full Host Bootdisk which uses tokens, or set Administer - Settings - Provisioning - Installation token lifetime to zero. This turns off the token enforcement and allows unauthenticated parties to use arbitrary MAC addresses in unattended requests to fetch provisioning kickstart with possibly sensitive data.
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 1 Oct 2026 · Last source change 7 Oct 2026, 06:12 UTC · CWE-203 · Observable Discrepancy

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-10-02
European sourceENISA EUVD · EUVD-2026-90971
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD awaiting enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:74503; removed remediation: access.redhat.com/RHSA-2026:74505; removed vendor advisory: access.redhat.com/RHSA-2026:74505.
    Before
    remediation: access.redhat.com/RHSA-2026:74505 · vendor advisory: access.redhat.com/RHSA-2026:74505
    After
    remediation: access.redhat.com/RHSA-2026:74503
    CNA ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:74505; added vendor advisory: access.redhat.com/RHSA-2026:74505; removed remediation: access.redhat.com/RHSA-2026:74503.
    Before
    remediation: access.redhat.com/RHSA-2026:74503
    After
    remediation: access.redhat.com/RHSA-2026:74505 · vendor advisory: access.redhat.com/RHSA-2026:74505
    access.redhat.com ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Satellite 6.16 for RHEL 8: 0:4.14.0.23-1.el8sat < *; Red Hat Satellite 6.16 for RHEL 9: 0:4.14.0.23-1.el9sat < *; Red Hat Satellite 6.18 for RHEL 9: 0:4.18.0.24-1.el9sat < *; Red Hat Satellite 6.19 for RHEL 9: 0:4.20.0.11-1.el9sat < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Satellite 6.16 for RHEL 8: 0:4.14.0.23-1.el8sat < *; Red Hat Satellite 6.16 for RHEL 9: 0:4.14.0.23-1.el9sat < *; Red Hat Satellite 6.17 for RHEL 9: 0:4.16.0.20-1.el9sat < *; Red Hat Satellite 6.18 for RHEL 9: 0:4.18.0.24-1.el9sat < *; Red Hat Satellite 6.19 for RHEL 9: 0:4.20.0.11-1.el9sat < *
    CNA ↗
  4. Vendor guidanceAuthoritative vendor guidance changed from remediation: access.redhat.com/CVE-2026-56098 to remediation: access.redhat.com/CVE-2026-56098.
    Before
    remediation: access.redhat.com/CVE-2026-56098
    After
    remediation: access.redhat.com/CVE-2026-56098
    Red Hat Product Security ↗
  5. Affected versionsThe structured affected or fixed version information changed.
    Before
    foreman-proxy-content as a component of Red Hat Satellite 6; katello as a component of Red Hat Satellite 6; katello-capsule as a component of Red Hat Satellite 6; katello-common as a component of Red Hat Satellite 6; katello-debug as a component of Red Hat Satellite 6; katello-service as a component of Red Hat Satellite 6; katello.src as a component of Red Hat Satellite 6; satellite:el8/rubygem-katello.src as a component of Red Hat Satellite 6 · Fixed: rubygem-katello-0:4.20.0.11-1.el9sat.noarch as a component of Red Hat Satellite 6.19 for RHEL 9; rubygem-katello-0:4.20.0.11-1.el9sat.src as a component of Red Hat Satellite 6.19 for RHEL 9
    After
    foreman-proxy-content as a component of Red Hat Satellite 6; katello as a component of Red Hat Satellite 6; katello-capsule as a component of Red Hat Satellite 6; katello-common as a component of Red Hat Satellite 6; katello-debug as a component of Red Hat Satellite 6; katello-service as a component of Red Hat Satellite 6; katello.src as a component of Red Hat Satellite 6; satellite:el8/rubygem-katello.src as a component of Red Hat Satellite 6 · Fixed: rubygem-katello-0:4.14.0.23-1.el8sat.noarch as a component of Red Hat Satellite 6.16 for RHEL 8; rubygem-katello-0:4.14.0.23-1.el8sat.src as a component of Red Hat Satellite 6.16 for RHEL 8; rubygem-katello-0:4.14.0.23-1.el9sat.noarch as a component of Red Hat Satellite 6.16 for RHEL 9; rubygem-katello-0:4.14.0.23-1.el9sat.src as a component of Red Hat Satellite 6.16 for RHEL 9; rubygem-katello-0:4.16.0.20-1.el9sat.noarch as a component of Red Hat Satellite 6.17 for RHEL 9; rubygem-katello-0:4.16.0.20-1.el9sat.src as a component of Red Hat Satellite 6.17 for RHEL 9; rubygem-katello-0:4.18.0.24-1.el9sat.noarch as a component of Red Hat Satellite 6.18 for RHEL 9; rubygem-katello-0:4.18.0.24-1.el9sat.src as a component of Red Hat Satellite 6.18 for RHEL 9; rubygem-katello-0:4.20.0.11-1.el9sat.noarch as a component of Red Hat Satellite 6.19 for RHEL 9; rubygem-katello-0:4.20.0.11-1.el9sat.src as a component of Red Hat Satellite 6.19 for RHEL 9
    Red Hat Product Security ↗
  6. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:74503; removed remediation: access.redhat.com/RHSA-2026:74504; removed vendor advisory: access.redhat.com/RHSA-2026:74504; 1 further removals.
    Before
    remediation: access.redhat.com/RHSA-2026:74504 · vendor advisory: access.redhat.com/RHSA-2026:74504 · vendor advisory: access.redhat.com/RHSA-2026:74506
    After
    remediation: access.redhat.com/RHSA-2026:74503
    CNA ↗
  7. Vendor guidanceAuthoritative vendor guidance changed: added remediation: access.redhat.com/RHSA-2026:74504; added vendor advisory: access.redhat.com/RHSA-2026:74504; removed remediation: access.redhat.com/RHSA-2026:74503; 1 further additions.
    Before
    remediation: access.redhat.com/RHSA-2026:74503
    After
    remediation: access.redhat.com/RHSA-2026:74504 · vendor advisory: access.redhat.com/RHSA-2026:74504 · vendor advisory: access.redhat.com/RHSA-2026:74506
    access.redhat.com ↗
  8. Affected versionsThe structured affected or fixed version information changed.
    Before
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Satellite 6.19 for RHEL 9: 0:4.20.0.11-1.el9sat < *
    After
    See the vendor and CVE records for the affected range. · Fixed: Red Hat Satellite 6.16 for RHEL 8: 0:4.14.0.23-1.el8sat < *; Red Hat Satellite 6.16 for RHEL 9: 0:4.14.0.23-1.el9sat < *; Red Hat Satellite 6.18 for RHEL 9: 0:4.18.0.24-1.el9sat < *; Red Hat Satellite 6.19 for RHEL 9: 0:4.20.0.11-1.el9sat < *
    CNA ↗
  9. ENISA EUVD mappingEUVD-2026-90971 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-90971"}
    ENISA EUVD ↗
  10. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
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-2026-56098 · cve.blacktree.nl