CVE-2025-20350
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk40th percentile - higher than 40% of all known CVEs
Summary
A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 running Cisco SIP Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This is due to a buffer overflow when processing HTTP packets. An attacker could exploit this by sending crafted HTTP input, causing the device to reload. To exploit, the phone must be registered to Cisco Unified Communications Manager and have Web Access enabled (disabled by default).
Risk Assessment
An attacker could cause unavailability of the phone device, potentially disrupting communication in the organization. However, additional conditions must be met (registration in UC Manager and Web Access enabled).
Recommendation
It is recommended to update the SIP software on the devices to the latest version containing the fix. Also, consider disabling Web Access if not required.
Other vulnerabilities in Cisco SIP Software
See all- CVE-2026-20281High
A vulnerability in Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 running SIP Software allows an unauthenticated, remote attacker to cause a DoS condition. It is due to improper memory management when processing HTTP packets, and exploitation involves sending a continuous stream of crafted HTTP packets.
- CVE-2025-20351Medium
A vulnerability in the web UI of Cisco Desk Phone 9800 Series, IP Phone 7800/8800 Series, and Video Phone 8875 running Cisco SIP Software allows an unauthenticated, remote attacker to conduct XSS attacks against a user of the web UI. The issue exists due to insufficient validation of user-supplied input. Exploitation requires the user to click a crafted link, and the phone must be registered to Cisco Unified Communications Manager with Web Access enabled (disabled by default).
Original NVD description (English source)
A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 running Cisco SIP Software could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to a buffer overflow when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending crafted HTTP input to the device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To exploit this vulnerability, the phone must be registered to Cisco Unified Communications Manager and have Web Access enabled. Web Access is disabled by default.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS