---
id: "CVE-2026-91420"
kind: "vulnerability"
aliases: ["CVE-2026-91420"]
title: "Oracle Siebel CRM Deployment: low-privilege HTTP user can modify critical data"
severity: "medium"
cvss: 6.5
epss: 0.00228
exploited: false
status: "open"
category: "vendor"
products: []
ecosystems: []
tags: ["enterprise", "oracle", "self-hosted", "siebel-crm", "vendor"]
not_affected_if: ["unknown"]
published_at: "2026-10-20T22:20:45+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-2026-91420", "first_seen_at": "2026-10-23T21:57:26+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-91420", "first_seen_at": "2026-10-25T12:38:52+00:00"}]
---

# Oracle Siebel CRM Deployment: low-privilege HTTP user can modify critical data

Oracle Siebel CRM Deployment, Server Infrastructure component, versions 17.0 through 26.9, has a flaw reachable over HTTP. A low-privileged attacker with network access can create, delete or modify critical data the product stores.

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

## How to check

- Confirm the Siebel CRM Deployment version in use and compare it with the affected range 17.0-26.9 (unknown how to read the exact build from the sources)
- Check Oracle's Siebel CRM security advisory for the patch level covering this CVE (unknown from the sources)

## Fix

- Apply the Oracle Siebel CRM Deployment patch or update that covers this CVE, per Oracle's Critical Patch Update guidance (exact fixed version: unknown)
- Restrict HTTP access to Siebel servers to trusted networks until patched (unknown from the sources)

## Timeline

- 2026-10-23T21:57:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91420
- 2026-10-25T12:38:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-91420

## From the sources

Vulnerability in the Siebel CRM Deployment product of Oracle Siebel CRM (component: Server Infrastructure).  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 Deployment.  Successful attacks of this vulnerability can result in  unauthorized creation, deletion or modification access to critical data or all Siebel CRM Deployment accessible data. CVSS 3.1 Base Score 6.5 (Integrity impacts).  CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/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_