CVE-2026-20230: Cisco Unified Communications Manager Server-Side Request Forgery (SSRF) Vulnerability

Patch now

HIGH 8.6EXPLOITEDREMOTEUPGRADE

CVE-2026-20230 is a high-severity flaw (CVSS 8.6) affecting unified communications manager, reported as exploited in the wild. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery (SSRF) attacks through an affected device. This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request t

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Exploited in the wild (CISA KEV)
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	8.6 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	88.2% (top 1%)
CISA exploited list	Yes, fix due 2026-06-28
Weakness	CWE-918
Published	2026-06-03
Last modified	2026-10-07

Publisher (CNA): Cisco Systems, Inc. · Vendor: cisco

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-03 18:16 UTCPublished CVE record published
2026-06-25Exploited Added to the CISA Known Exploited Vulnerabilities list
2026-06-28Deadline CISA due date for US federal agencies to patch
2026-10-07 19:17 UTCUpdated Record last modified

cisco unified communications manager UPGRADE

Affected: >= 14.0 and < 14su6 · >= 15.0 and <= 15su4a

Fixed in: 14su6

Safe to downgrade to: a release before 14.0

1. Check installed version

apt-cache policy unified-communications-manager || rpm -q unified-communications-manager || unified-communications-manager --version

2. UPGRADE to 14su6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade unified-communications-manager

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade unified-communications-manager

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 14.0 (Debian / Ubuntu)

apt-cache madison unified-communications-manager sudo apt install unified-communications-manager=<VERSION_BEFORE_14.0> sudo apt-mark hold unified-communications-manager

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list unified-communications-manager sudo dnf downgrade unified-communications-manager-<VERSION_BEFORE_14.0> sudo dnf versionlock add unified-communications-manager

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Fedora 46 · arm-none-eabi-binutils-cs · FIXED · 2.47-1.fc46 · FEDORA-2026-7498616952 · source

sudo dnf upgrade --advisory=FEDORA-2026-7498616952

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: HORKimhab/CVE-2026-20230 (1 stars)
GitHub PoC: W5M1n9/Cisco-Unified-Communications-Manager-Server-Side-Forgery-Request-Vulnerability-CVE-2026-20230 (1 stars)
GitHub PoC: HalilDeniz/CVE-2026-20230-Scanner (0 stars)
Write-up: sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssrf-c

Verify at the official source NVD · CVE Program · CISA KEV catalog · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-20230?

unified communications manager: upgrade to 14su6. Exact commands for each OS are on this page.

Is CVE-2026-20230 being exploited?

Yes. CVE-2026-20230 is on the CISA Known Exploited Vulnerabilities list, so treat it as patch-now.

What does CVE-2026-20230 affect?

CVE-2026-20230 affects unified communications manager. Severity is high (CVSS 8.6). A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery

How urgent is CVE-2026-20230?

Priority 90/100. High severity; EPSS top 1%: very likely to be exploited; Exploited in the wild (CISA KEV); Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Cisco vulnerabilities

References

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