What is CVE-2026-20230?
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 to an affected device. A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root. Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root. Note: To exploit this vulnerability, the WebDialer service must be enabled. WebDialer is disabled by default.
The record classifies CVE-2026-20230 under weakness class CWE-918. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on integrity. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 131 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 8.6 — HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N - EPSS (FIRST)
- 41.6% probability of exploitation in the next 30 days, higher than 98.5% of all scored CVEs
- CISA KEV
- Listed since 2026-06-25, federal remediation deadline 2026-06-28
- Threadlinqs priority
- 9/10 — CISA KEV-listed, which Threadlinqs floors at 9
- Published
- 2026-06-03, last modified 2026-06-26
Is CVE-2026-20230 being exploited?
CISA added CVE-2026-20230 to the Known Exploited Vulnerabilities catalog on 2026-06-25, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2026-06-28 under BOD 22-01. Weaponised exploit code for CVE-2026-20230 is publicly available. 3 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 67 in the Threadlinqs vulnerability feed.
Affected products and versions
- Cisco: Unified Communications Manager
How to fix CVE-2026-20230
Vendor advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssrf-cXPnHcW. Because CVE-2026-20230 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2026-06-28. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.
Threat activity tracking CVE-2026-20230
10 tracked threats in the Threadlinqs corpus reference CVE-2026-20230, either in the campaign’s CVE list or as an indicator on the campaign record.
- Microsoft July 2026 Patch Tuesday: 570 Flaws Fixed, 3 Zero-Days Including AD FS and SharePoint Privilege Escalation — CRITICAL · 2026-07-14
- CVE-2026-20230: Cisco Unified Communications Manager WebDialer SSRF Actively Exploited to Drop Tor-Routed JSP Webshells via Rogue Apache Axis Service, CISA Sets June 28 Deadline — CRITICAL · 2026-07-11
- Cisco Unified CM / Unified CM SME SSRF Vulnerability (CVE-2026-20230) — WebDialer File-Write to Root, Actively Exploited, Added to CISA KEV — CRITICAL · 2026-07-11
- CISA BOD 26-04: Risk-Based Vulnerability Remediation and CISO Reporting Mandate for FCEB Agencies — MEDIUM · 2026-07-06
- CVE-2026-20230: Active Exploitation of Cisco Unified CM WebDialer SSRF Flaw Leading to Root-Level Compromise — HIGH · 2026-07-02
- Active Exploitation of Cisco Unified Communications Manager WebDialer SSRF (CVE-2026-20230) and Catalyst SD-WAN Manager Root Privilege-Escalation Zero-Day (CVE-2026-20245) — CRITICAL · 2026-07-01
- CISA KEV: PTC Windchill RCE and Cisco Unified CM SSRF - Critical Remote Code Execution Vulnerabilities — CRITICAL · 2026-06-28
- CISA KEV: Cisco Unified Communications Manager SSRF to Webshell (CVE-2026-20230) Actively Exploited — CRITICAL · 2026-06-27
- CISA KEV Adds CVE-2026-12569 (PTC Windchill/FlexPLM Unauthenticated RCE via Deserialization) and CVE-2026-20230 (Cisco Unified CM WebDialer SSRF to Root) — CRITICAL · 2026-06-25
- Cisco Unified CM WebDialer SSRF (CVE-2026-20230) — Unauthenticated SSRF Chained to Arbitrary File Write Enabling Root Compromise; Public PoC Available — CRITICAL · 2026-06-06
Sources
Enriched from CVE.org, NVD, FIRST EPSS, CISA KEV, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.