Medium

CVE-2026-91428 — Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open…

Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open UI). Supported versions that are affected are 17.0-26.9. Easily exploitable vulnerability allows unauthenticated attacker with network access via HTTP to compromise Siebel CRM End User. Successful attacks require human interaction from a person other than the attacker. Successful attacks of this vulnerability can result in unauthorized update, insert or delete access to some of Siebel CRM End User accessible data. CVSS 3.1 Base Score 4.3 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N).

Published Oct 20, 2026 · Updated Oct 20, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: oracle

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

—

No EPSS score.

Affects

Oracle

Siebel CRM End User

CVSS base

4.3

Medium · 2 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Oracle Siebel CRM End User).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Oracle	Siebel CRM End User	≥ 17.0 and ≤ 26.9	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
4.3	CVSS 3.1	Medium	2.8	1.4	secalert_us@oracle.com via NIST National Vulnerability Database
4.3	CVSS 3.1	Medium	—	—	oracle via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N (score shown at the top: secalert_us@oracle.com)

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · oracle corporation/siebel crm end user
Oct 20, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 20, 2026
CVSS changed · 4.3
Oct 20, 2026 · NIST National Vulnerability Database
Source status changed · → Received
Oct 20, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 20, 2026 · NIST National Vulnerability Database
CVE published
Oct 20, 2026 · oracle

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 20, 2026 – Oct 20, 2026

References

1 on the record

www.oracle.com/security-alerts/cpuoct2026.html
vendor-advisory, NIST National Vulnerability Database

Elsewhere on this site

Oracle
every CVE for this vendor

Related CVEs (same products)

High CVE-2026-91445 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component… 16h
Medium CVE-2026-91432 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open… 16h
Medium CVE-2026-91431 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open… 16h
Medium CVE-2026-91412 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open… 16h
Medium CVE-2026-91389 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open… 16h
Medium CVE-2026-91390 Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open… 16h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No FIRST EPSS score.
No fixed version, patch or mitigation documented.
No CISA SSVC assessment.
No CWE classification.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-91428 is "Vulnerability in the Siebel CRM End User product of Oracle Siebel CRM (component: Open…", rated Medium. It affects Siebel CRM End User (Oracle); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 4.3 describes technical severity. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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