Cisco Unified CM Flaw Exploited After PoC Reveals File

An unauthenticated server-side request forgery (SSRF) flaw exists in Cisco Unified Communications Manager (Unified CM) and Unified CM Session Management Edition (Unified CM SME), caused by improper input validation of specific HTTP requests. An attacker triggers it by sending a crafted HTTP request to the device's WebDialer service, which must be enabled for exploitation (it is disabled by default). Successful exploitation lets the attacker write files to the underlying operating system, which can later be used to elevate privileges to root — the reason Cisco assigned a Critical Security Impact Rating despite the 8.6 (High) CVSS base score. Organizations running affected Unified CM or Unified CM SME deployments, particularly those with WebDialer enabled and reachable from untrusted networks, are exposed. The flaw is being exploited in the wild: public exploit references appeared in mid-June 2026, and CISA added it to the Known Exploited Vulnerabilities catalog on 2026-06-25, with EPSS indicating an ~88% probability of exploitation within 30 days.

Do: Upgrade affected Unified CM and Unified CM SME deployments to the fixed release cited in Cisco's advisory (specific version not provided in this dataset), prioritizing internet-exposed systems per CISA BOD 26-04 requirements. Confirm whether the WebDialer service is enabled and disable it if unused, or restrict network access to it. Check device logs for crafted HTTP requests hitting WebDialer endpoints and unexpected file writes on the underlying OS that could indicate prior exploitation.

CVE-2026-20262 is a directory/path traversal vulnerability (CWE-22) in Cisco Catalyst SD-WAN Manager, the central management component of Cisco's enterprise SD-WAN solution. An authenticated, remote attacker can supply crafted input containing traversal sequences that escape the intended directory, allowing the attacker to create a new file or overwrite any file on the affected system's filesystem. Overwriting arbitrary files can enable configuration tampering, persistence, or privilege escalation on the management appliance depending on which file is targeted. Any organization running Cisco Catalyst SD-WAN Manager is affected, with greatest risk where the management interface is reachable by broad user populations or from the internet. CISA added the flaw to the Known Exploited Vulnerabilities catalog on 2026-06-15, indicating exploitation in the wild; no public proof-of-concept is known, ransomware association is unknown, CVSS is not yet scored, and EPSS assigns a 28.2% probability of exploitation within 30 days (98th percentile).

Do: Apply the fixed release per Cisco's advisory (specific fixed versions are not provided in this data set, so consult Cisco's security notice) and follow CISA's KEV required action, including BOD 26-04 timelines for federal agencies and cloud service use. Until patched, restrict access to the SD-WAN Manager management interface to trusted management networks, enforce strong authentication, and audit the filesystem for unexpectedly created or recently modified files that could indicate exploitation. Evaluate each instance's internet exposure and prioritize internet-reachable management appliances for immediate remediation.