Cisco Security Advisory
Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Vulnerabilities
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CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:X/RL:X/RC:X
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Multiple vulnerabilities in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 running Cisco Session Initiation Protocol (SIP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or conduct a cross-site scripting (XSS) attack against a user of the web UI.
Note: To exploit these vulnerabilities, the phone must be registered to Cisco Unified Communications Manager and have Web Access enabled. Web Access is disabled by default.
For more information about these vulnerabilities, see the Details section of this advisory.
Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
This advisory is available at the following link:
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-dos-FPyjLV7A
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Vulnerable Products
These vulnerabilities affect the following Cisco products if they are running a vulnerable release of Cisco SIP Software, are registered to Cisco Unified Communications Manager, and have Web Access enabled:
- Desk Phone 9800 Series
- IP Phone 7800 Series
- IP Phone 8800 Series
- Video Phone 8875
The Web Access feature is disabled by default.
For information about which Cisco software releases are vulnerable, see the Fixed Software section of this advisory.
Determine Whether Web Access Is Enabled
To determine whether Web Access is enabled, use the following steps:
- Press the gear icon on the front of the phone to access the Settings menu.
- Choose Admin settings > Network Setup > Ethernet setup or Wi-Fi client setup > IPv4 setup. See the IP address for the phone.
- On a device that has access to the internet, open a web browser and enter the IP address in the address bar. Press Enter.
If the Device Information screen appears in the web browser, then Web Access is enabled on the phone.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory are known to be affected by these vulnerabilities.
Cisco has confirmed that these vulnerabilities do not affect Cisco IP Phone 7800 Series or 8800 Series that are running Cisco Multiplatform Firmware.
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The vulnerabilities are not dependent on one another. Exploitation of one of the vulnerabilities is not required to exploit the other vulnerability. In addition, a software release that is affected by one of the vulnerabilities may not be affected by the other vulnerability.
Details about the vulnerabilities are as follows:
Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software DoS Vulnerability
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.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwn51601, CSCwn60480, CSCwn60481, CSCwn60482, CSCwn60484, CSCwn60491, CSCwn60492, CSCwn60493, CSCwn60494
CVE ID: CVE-2025-20350
Security Impact Rating (SIR): High
CVSS Base Score: 7.5
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software XSS Vulnerability
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 conduct XSS attacks against a user of the web UI.
This vulnerability exists because the web UI of an affected device does not sufficiently validate user-supplied input. An attacker could exploit this vulnerability by persuading a user to click a crafted link. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected interface or access sensitive, browser-based information.
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.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Bug ID(s): CSCwn51683, CSCwn58671, CSCwn58673, CSCwn58674, CSCwn58676, CSCwn58683, CSCwn58684, CSCwn58685, CSCwn58687
CVE ID: CVE-2025-20351
Security Impact Rating (SIR): Medium
CVSS Base Score: 6.1
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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There are no workarounds that address these vulnerabilities. However, disabling Web Access mitigates these vulnerabilities.
To enable or disable Web Access on a specific device, follow these steps:
- Log in to the Communications Manager to which the phone is registered using administrative privileges, which allow modification of devices.
- Choose Device > Phone.
- Enter the search criteria in the search box and click Find.
- Choose the appropriate device from the Device Name list.
- Under Web Access, use the toggle button to choose Enabled or Disabled, and click Save.
To verify that the desired state has been set, enter the IP address of the phone into a browser window on a device that has internet access, and click Enter.
To enable or disable Web Access on multiple devices, use the Bulk Admin Tool (BAT) as detailed in the Bulk Administration Guide for Cisco Unified Communications Manager.
While this mitigation has been deployed and was proven successful in a test environment, customers should determine the applicability and effectiveness in their own environment and under their own use conditions. Customers should be aware that any workaround or mitigation that is implemented may negatively impact the functionality or performance of their network based on intrinsic customer deployment scenarios and limitations. Customers should not deploy any workarounds or mitigations before first evaluating the applicability to their own environment and any impact to such environment.
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Cisco considers any workarounds and mitigations to be temporary solutions until an upgrade to a fixed software release is available. To fully remediate these vulnerabilities and avoid future exposure as described in this advisory, Cisco strongly recommends that customers upgrade to the fixed software indicated in this advisory.
Fixed Releases
In the following tables, the left column lists Cisco software releases. The center and right columns indicate whether a release is affected by the vulnerabilities that are described in this advisory and the first release that includes the fix for these vulnerabilities. Customers are advised to upgrade to an appropriate fixed software release as indicated in this section.
Desk Phone 9800 Series
Cisco SIP Software Release First Fixed Release for CVE-2025-20350 First Fixed Release for CVE-2025-20351 3 3.3(1) 3.3(1) IP Phone 7800 and 8800 Series
Cisco SIP Software Release First Fixed Release for CVE-2025-20350 First Fixed Release for CVE-2025-20351 Earlier than 14.3 Migrate to a fixed release. Migrate to a fixed release. 14.3 14.3(1)SR2 Migrate to a fixed release. 14.4 Not vulnerable. 14.4(1) IP Phone 8821
Cisco SIP Software Release First Fixed Release for CVE-2025-20350 First Fixed Release for CVE-2025-20351 Earlier than 11 Migrate to a fixed release. Migrate to a fixed release. 11 11.0(6)SR7 11.0(6)SR7 Video Phone 8875
Cisco SIP Software Release First Fixed Release for CVE-2025-20350 First Fixed Release for CVE-2025-20351 2.3(1)SR1 and earlier Migrate to a fixed release. Migrate to a fixed release. 3 3.3(1) 3.3(1) The Cisco Product Security Incident Response Team (PSIRT) validates only the affected and fixed release information that is documented in this advisory.
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The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerabilities that are described in this advisory.
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These vulnerabilities were found during internal security testing by Kent Yoder of the Cisco Advanced Security Initiatives Group (ASIG).
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Show LessVersion Description Section Status Date 1.0 Initial public release. - Final 2025-OCT-15
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SOFTWARE DOWNLOADS AND TECHNICAL SUPPORT
The Cisco Support and Downloads page on Cisco.com provides information about licensing and downloads. This page can also display customer device support coverage for customers who use the My Devices tool. Please note that customers may download only software that was procured from Cisco directly or through a Cisco authorized reseller or partner and for which the license is still valid.
Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC). Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade.
When considering software upgrades, customers are advised to regularly consult the advisories for the relevant Cisco products to determine exposure and a complete upgrade solution. In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
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Copies or summaries of the information contained in this Security Advisory may lack important information or contain factual errors. Customers are advised to visit the Cisco Security Advisories page for the most recent version of this Security Advisory. The Cisco Product Security Incident Response Team (PSIRT) assesses only the affected and fixed release information that is documented in this advisory. See the Cisco Security Vulnerability Policy for more information.