CVE-2025-20309 — Cisco Unified Communications Manager
As of 2026-02-26, CVE-2025-20309 is a CRITICAL-severity vulnerability in Cisco Unified Communications Manager, CVSS v3.1 10, EPSS 1.1% (65.1th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2025-20309, most recently “CVE-2026-20230: Active Exploitation of Cisco Unified CM WebDialer SSRF Flaw Leading to Root-Level Compromise”.
Last updated: 2026-02-26
What is CVE-2025-20309?
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 log in to an affected device using the root account, which has default, static credentials that cannot be changed or deleted. This vulnerability is due to the presence of static user credentials for the root account that are reserved for use during development. An attacker could exploit this vulnerability by using the account to log in to an affected system. A successful exploit could allow the attacker to log in to the affected system and execute arbitrary commands as the root user.
The record classifies CVE-2025-20309 under weakness class CWE-798. 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 confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 456 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 10 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - EPSS (FIRST)
- 1.1% probability of exploitation in the next 30 days, higher than 65.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 7.6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2025-07-02, last modified 2026-02-26
Is CVE-2025-20309 being exploited?
No public exploitation evidence for CVE-2025-20309 is recorded in the sources Threadlinqs tracks — CISA KEV, Exploit-DB, public proof-of-concept repositories and ProjectDiscovery Nuclei — as of 2026-02-26. That is an absence of evidence in those feeds, not a guarantee that the vulnerability is unexploited.
Affected products and versions
- Cisco: Unified Communications Manager
How to fix CVE-2025-20309
The record marks a vendor fix as available for CVE-2025-20309. Patch reference: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssh-m4UBdpE7. Vendor advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssh-m4UBdpE7. 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-2025-20309
1 tracked threat in the Threadlinqs corpus references CVE-2025-20309, either in the campaign’s CVE list or as an indicator on the campaign record.
- CVE-2026-20230: Active Exploitation of Cisco Unified CM WebDialer SSRF Flaw Leading to Root-Level Compromise — HIGH · 2026-07-02
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.
Other references
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