CVE-2026-21926Network attack vector

Unauthenticated denial of service via TLS

Published Jan 20, 2026 · Updated Jan 20, 2026

Denial of service in Server Infrastructure in Oracle Siebel CRM Deployment 17.0 through 25.2 allows remote attackers to crash it via TLS. Oracle has not published the faulty routine or the malformed TLS input that triggers the failure. No credentials or user interaction are required; successful requests can hang the deployment or cause frequently repeatable crashes, without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability0.37%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Server Infrastructure in Oracle Siebel CRM Deployment 17.0 through 25.2 allows remote attackers to crash it via TLS. Oracle has not published the faulty routine or the malformed TLS input that triggers the failure. No credentials or user interaction are required; successful requests can hang the deployment or cause frequently repeatable crashes, without reported data disclosure or modification.

The record

CVE
CVE-2026-21926
Published
Jan 20, 2026
Updated
Jan 20, 2026
Vendor
Oracle
Product
Siebel CRM Deployment
Classifications
T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=17.0 <=25.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Oracle · Siebel CRM Deploymentversion=17.0 <=25.2

Published CVSS scores

7.5OracleCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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