---
id: "CVE-2026-91390"
kind: "vulnerability"
aliases: ["CVE-2026-91390"]
title: "Oracle Siebel CRM End User: Open UI flaw exposes some data to changes"
severity: "medium"
cvss: 5.4
epss: 0.00195
exploited: false
status: "open"
category: "vendor"
products: []
ecosystems: []
tags: ["oracle", "self-hosted", "siebel-crm", "vendor"]
not_affected_if: []
published_at: "2026-10-20T22:20:42+00:00"
first_seen_at: "2026-10-23T21:57:26+00:00"
updated_at: "2026-10-25T12:38:52+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91390", "first_seen_at": "2026-10-23T21:57:26+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91390", "first_seen_at": "2026-10-25T12:38:52+00:00"}]
---

# Oracle Siebel CRM End User: Open UI flaw exposes some data to changes

Oracle Siebel CRM End User has a flaw in its Open UI component that lets a low-privileged user over HTTP read and change a subset of accessible data when another person interacts with a crafted request. The sources say the attack can also affect other products (scope change), with a CVSS 3.1 base score of 5.4.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- unknown

## Timeline

- 2026-10-23T21:57:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91390
- 2026-10-25T12:38:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91390

## From the sources

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 low privileged attacker with network access via HTTP to compromise Siebel CRM End User.  Successful attacks require human interaction from a person other than the attacker and while the vulnerability is in Siebel CRM End User, attacks may significantly impact additional products (scope change). Successful attacks of this vulnerability can result in  unauthorized update, insert or delete access to some of Siebel CRM End User accessible data as well as  unauthorized read access to a subset of Siebel CRM End User accessible data. CVSS 3.1 Base Score 5.4 (Confidentiality and Integrity impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N).

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_