CVE-2025-20335: Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Firmware Information Arbitrary File Write Vulnerability

Published Sep 3, 2025
·
Updated

A vulnerability in the directory permissions of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 could allow an unauthenticated, remote attacker to write arbitrary files on an affected device. This vulnerability is due to a lack of proper authentication controls. An attacker could exploit this vulnerability by sending a crafted request to an affected device. A successful exploit could allow the attacker to perform arbitrary file writes to specific directories in the underlying operating system. Note: To exploit this vulnerability, Web Access must be enabled on the phone. Web Access is disabled by default.

Affected Software

69 affected components
Cisco Desk Phone 9800 Series
Cisco IP Phone 7800 Series
Cisco IP Phone 8800 Series
Cisco Video Phone 8875
All of the following
Cisco Desk Phone 9841 Firmware>=3.0\(1\)<3.3\(1\)
Cisco Desk Phone 9841
All of the following
Cisco Desk Phone 9851 Firmware>=3.0\(1\)<3.3\(1\)
Cisco Desk Phone 9851
All of the following
Cisco Desk Phone 9861 Firmware>=3.0\(1\)<3.3\(1\)
Cisco Desk Phone 9861
All of the following
Cisco Desk Phone 9871 Firmware>=3.0\(1\)<3.3\(1\)
Cisco Desk Phone 9871
All of the following
Any of the following
Cisco Ip Phone 7811 Firmware<14.3\(1\)
Cisco Ip Phone 7811 Firmware=14.3\(1\)
Cisco Ip Phone 7811 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 7811
All of the following
Any of the following
Cisco Ip Phone 7821 Firmware<14.3\(1\)
Cisco Ip Phone 7821 Firmware=14.3\(1\)
Cisco Ip Phone 7821 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 7821
All of the following
Any of the following
Cisco Ip Phone 7841 Firmware<14.3\(1\)
Cisco Ip Phone 7841 Firmware=14.3\(1\)
Cisco Ip Phone 7841 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 7841
All of the following
Any of the following
Cisco Ip Phone 7861 Firmware<14.3\(1\)
Cisco Ip Phone 7861 Firmware=14.3\(1\)
Cisco Ip Phone 7861 Firmware=14.3\(1\)-sr1
Cisco IP Phone 7861
All of the following
Any of the following
Cisco Ip Phone 8811 Firmware<14.3\(1\)
Cisco Ip Phone 8811 Firmware=14.3\(1\)
Cisco Ip Phone 8811 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8811
All of the following
Any of the following
Cisco Ip Phone 8841 Firmware<14.3\(1\)
Cisco Ip Phone 8841 Firmware=14.3\(1\)
Cisco Ip Phone 8841 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8841
All of the following
Any of the following
Cisco Ip Phone 8845 Firmware<14.3\(1\)
Cisco Ip Phone 8845 Firmware=14.3\(1\)
Cisco Ip Phone 8845 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8845
All of the following
Any of the following
Cisco Ip Phone 8851 Firmware<14.3\(1\)
Cisco Ip Phone 8851 Firmware=14.3\(1\)
Cisco Ip Phone 8851 Firmware=14.3\(1\)-sr1
Cisco IP Phone 8851
All of the following
Any of the following
Cisco Ip Phone 8851nr Firmware<14.3\(1\)
Cisco Ip Phone 8851nr Firmware=14.3\(1\)
Cisco Ip Phone 8851nr Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8851nr
All of the following
Any of the following
Cisco Ip Phone 8861 Firmware<14.3\(1\)
Cisco Ip Phone 8861 Firmware=14.3\(1\)
Cisco Ip Phone 8861 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8861
All of the following
Any of the following
Cisco Ip Phone 8865 Firmware<14.3\(1\)
Cisco Ip Phone 8865 Firmware=14.3\(1\)
Cisco Ip Phone 8865 Firmware=14.3\(1\)-sr1
Cisco Ip Phone 8865
All of the following
Any of the following
Cisco Video Phone 8875 Firmware<2.3\(1\)
Cisco Video Phone 8875 Firmware>=3.0\(1\)<3.3\(1\)
Cisco Video Phone 8875 Firmware=2.3\(1\)
Cisco Video Phone 8875 Firmware=2.3\(1\)-sr1
Cisco Video Phone 8875
All of the following
Any of the following
Cisco Ip Phone 8821 Firmware<11.0\(6\)
Cisco Ip Phone 8821 Firmware=11.0\(6\)
Cisco Ip Phone 8821 Firmware=11.0\(6\)-sr1
Cisco Ip Phone 8821 Firmware=11.0\(6\)-sr2
Cisco Ip Phone 8821 Firmware=11.0\(6\)-sr4
Cisco Ip Phone 8821 Firmware=11.0\(6\)-sr5
Cisco Ip Phone 8821 Firmware=11.0\(6\)-sr6
Cisco IP Phone 8821

Event History

Sep 3, 2025
CVE Published
via MITRE·05:41 PM
Data Sourced
via MITRE·05:41 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·06:15 PM
DescriptionSeverityWeaknessAffected Software
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Frequently Asked Questions

1

What is the severity of CVE-2025-20335?

CVE-2025-20335 has a high severity rating due to the potential for remote, unauthenticated access leading to arbitrary file writes.

2

How do I fix CVE-2025-20335?

To fix CVE-2025-20335, update affected Cisco Desk Phone and IP Phone devices to the latest firmware version provided by Cisco.

3

Which devices are affected by CVE-2025-20335?

CVE-2025-20335 affects Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 Series, Cisco IP Phone 8800 Series, and Cisco Video Phone 8875.

4

What type of attack is possible with CVE-2025-20335?

CVE-2025-20335 allows an unauthenticated remote attacker to write arbitrary files on the affected devices.

5

Is there a workaround for CVE-2025-20335?

There are currently no known workarounds for CVE-2025-20335, and patching is the recommended action.

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