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Siebel Customer Relationship Management DeploymentApplication · Oracle

CVE-2026-21926

HIGH · 7.5 CVSS v3.1 Published 2026-01-20
Fix available
A fix is available. Upgrade to after 25.2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Vulnerability in the Siebel CRM Deployment product of Oracle Siebel CRM (component: Server Infrastructure). Supported versions that are affected are 17.0-25.2. Easily exploitable vulnerability allows unauthenticated attacker with network access via TLS to compromise Siebel CRM Deployment. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of Siebel CRM Deployment. CVSS 3.1 Base Score 7.5 (Availability impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A denial-of-service vulnerability in Oracle Siebel CRM Deployment's Server Infrastructure component allows unauthenticated remote attackers to cause complete service hang or repeatable crashes via network access over TLS. The vulnerability affects versions 17.0 through 25.2 and is easily exploitable without any authentication or user interaction.

MitigationApply the Oracle Critical Patch Update for Siebel CRM that addresses CVE-2026-21926. Until the patch is available, consider network segmentation to limit exposure and monitoring for unusual TLS traffic patterns targeting the Siebel Server Infrastructure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Siebel Customer Relationship Management DeploymentApplication
Affected:>= 17.0, <= 25.2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Oracle Siebel CRM deployment is installed
    Locate the Siebel installation directory or check system inventory for Oracle Siebel Customer Relationship Management components. Common installation paths include SIEBEL_HOME directory under /oracle/ or C:\oracle\siebel\
    Affected if Oracle Siebel CRM Deployment software is present on the system
  2. Identify the Siebel CRM Deployment version
    Check the installed Siebel version using the Siebel Gateway or Siebel Server configuration. The version is typically displayed in the Siebel Enterprise Manager, Siebel Gateway Registry, or can be retrieved via the 'sweinst -version' command from the Siebel bin directory
    Affected if The installed version falls within the range 17.0 through 25.2 inclusive
  3. Verify Server Infrastructure component is in use
    Check if the Siebel Server Infrastructure component (also known as Siebel Server or Siebel Enterprise Server) is configured and running. This can be verified through Siebel Gateway status, Siebel Server manager, or by checking for running Siebel Server processes
    Affected if The Server Infrastructure component is configured and active within the Siebel deployment
  4. Confirm TLS network exposure of Siebel Server Infrastructure
    Review network configuration to determine if the Siebel Server Infrastructure ports are exposed over TLS. Check Siebel Server connection configuration files (such as sweat.cfg or eapps.cfg) for TLS-enabled endpoints, and scan network ports for Siebel services accepting TLS connections
    Affected if The Server Infrastructure component is accessible over TLS on network ports (typically port 443 or custom TLS ports for eBusiness Applications)

The environment is affected if Oracle Siebel CRM Deployment version 17.0 through 25.2 is installed with the Server Infrastructure component exposed over the network using TLS.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Upgrade available Upgrade to a release after 25.2
Interim mitigation

Apply the Oracle Critical Patch Update for Siebel CRM that addresses CVE-2026-21926. Until the patch is available, consider network segmentation to limit exposure and monitoring for unusual TLS traffic patterns targeting the Siebel Server Infrastructure.

Fix this in Siebel Customer Relationship Management Deployment Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,928.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-21926 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data