---
id: "CVE-2026-76474"
kind: "vulnerability"
aliases: ["CVE-2026-76474"]
title: "Cisco Unified CM and Unity Connection: improper authentication flaw, critical"
severity: "critical"
cvss: 9.8
epss: 0.00357
exploited: false
status: "open"
category: "infrastructure"
products: [{"name": "Cisco Unified Communications Manager", "fixed": ["15SU5"], "affected": "14 (all SU), 15 through 15SU4a", "ecosystem": "vendor"}, {"name": "Cisco Unity Connection", "fixed": ["15SU5"], "affected": "14 (all SU), 15 through 15SU4", "ecosystem": "vendor"}, {"name": "Cisco Unified CM IM&P", "fixed": ["15SU5"], "affected": "14 (all SU), 15 through 15SU4", "ecosystem": "vendor"}, {"name": "Cisco Emergency Responder", "fixed": ["15SU5"], "affected": "14 (all SU), 15 through 15SU4", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["cisco", "infrastructure", "network", "self-hosted", "unauthenticated", "unified-cm", "unity-connection", "voice"]
not_affected_if: ["managed-hosting"]
published_at: "2026-10-21T17:19:07+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-24T13:15:54+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-76474", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "analyst", "url": null, "first_seen_at": "2026-10-23T22:29:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-76474", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# Cisco Unified CM and Unity Connection: improper authentication flaw, critical

Cisco Unified Communications Manager, Unity Connection, IM&P and Emergency Responder have an authentication bypass (CWE-287) found in an internal review. The sources do not say exactly what an attacker can reach after bypassing the check, but the CVSS score is 9.8 and the flaw needs no account.

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

## Affected

- vendor:Cisco Unified Communications Manager affected 14 (all SU), 15 through 15SU4a fixed 15SU5
- vendor:Cisco Unity Connection affected 14 (all SU), 15 through 15SU4 fixed 15SU5
- vendor:Cisco Unified CM IM&P affected 14 (all SU), 15 through 15SU4 fixed 15SU5
- vendor:Cisco Emergency Responder affected 14 (all SU), 15 through 15SU4 fixed 15SU5

## How to check

Check the installed release with the CUCM admin page or CLI command 'show version active' and compare it to the fixed release 15SU5.

## Fix

Upgrade to 15SU5 (affected 15 through 15SU4 and all 14 SU releases per the advisory data); for 14, the sources give no fixed release.

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-76474
- 2026-10-23T22:29:53+00:00 analyst — Read Cisco advisory cisco-sa-voice-hardening-twgbH9e3 (via fetch summary): fixed 15SU5; 14 has no named fixed release; no workarounds; not known exploited. Affected list from OpenCVE. Sibling CVEs 76473,76475-76479,76481 are in the same advisory. Exact fixed 14 release and specific vulnerable component unknown; the advisory does not say.
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-76474

## Documents

- [advisory] Cisco Unified Communications Products Security Hardening Release: October 2026 https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-voice-hardening-twgbH9e3
- [mentions] OpenCVE CVE-2026-76474 (affected version list) https://app.opencve.io/cve/CVE-2026-76474

## From the sources

As part of Cisco's ongoing commitment to proactive security and product quality, engineering teams for Cisco Emergency Responder, Cisco Prime Collaboration Deployment, Cisco Unified Communications Manager (Unified CM), Cisco Unified Communications Manager IM & Presence Service (Unified CM IM&P), Cisco Unified Communications Manager Session Management Edition (Unified CM SME), and Cisco Unity Connection have conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-76474 are related to issues concerning improper authentication that are grouped under the Common Weakness Enumeration (CWE) Class CWE-287.

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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_