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5.3
MEDIUM CVSS 3.1
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
Description

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.

INFO

Published Date :

Sept. 3, 2025, 6:15 p.m.

Last Modified :

Jan. 5, 2026, 2:49 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2025-20335 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Cisco ip_phone_8821_firmware
2 Cisco ip_phone_7811_firmware
3 Cisco ip_phone_7821_firmware
4 Cisco ip_phone_7841_firmware
5 Cisco ip_phone_7861_firmware
6 Cisco ip_phone_8811_firmware
7 Cisco ip_phone_8841_firmware
8 Cisco ip_phone_8845_firmware
9 Cisco ip_phone_8851_firmware
10 Cisco ip_phone_8861_firmware
11 Cisco ip_phone_8865_firmware
12 Cisco video_phone_8875_firmware
13 Cisco ip_phone_7861
14 Cisco ip_phone_8851
15 Cisco ip_phone_7811
16 Cisco ip_phone_7821
17 Cisco ip_phone_7841
18 Cisco ip_phone_8811
19 Cisco ip_phone_8841
20 Cisco ip_phone_8845
21 Cisco ip_phone_8861
22 Cisco ip_phone_8865
23 Cisco ip_phone_8821
24 Cisco video_phone_8875
25 Cisco desk_phone_9871_firmware
26 Cisco desk_phone_9871
27 Cisco desk_phone_9841_firmware
28 Cisco desk_phone_9841
29 Cisco desk_phone_9851_firmware
30 Cisco desk_phone_9851
31 Cisco desk_phone_9861_firmware
32 Cisco desk_phone_9861
33 Cisco ip_phone_8851nr
34 Cisco ip_phone_8851nr_firmware
: Total Affected Vendor : 1 | Products : 34
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM MITRE-CVE
Solution
Address directory permission issues by applying vendor patches for affected Cisco phone models.
  • Update Cisco Desk Phone 9800 Series devices.
  • Update Cisco IP Phone 7800 Series devices.
  • Update Cisco IP Phone 8800 Series devices.
  • Update Cisco Video Phone 8875 devices.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2025-20335.

URL Resource
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-write-g3kcC5Df Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2025-20335 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2025-20335 weaknesses.

CAPEC-19: Embedding Scripts within Scripts Embedding Scripts within Scripts CAPEC-441: Malicious Logic Insertion Malicious Logic Insertion CAPEC-478: Modification of Windows Service Configuration Modification of Windows Service Configuration CAPEC-479: Malicious Root Certificate Malicious Root Certificate CAPEC-502: Intent Spoof Intent Spoof CAPEC-503: WebView Exposure WebView Exposure CAPEC-536: Data Injected During Configuration Data Injected During Configuration CAPEC-546: Incomplete Data Deletion in a Multi-Tenant Environment Incomplete Data Deletion in a Multi-Tenant Environment CAPEC-550: Install New Service Install New Service CAPEC-551: Modify Existing Service Modify Existing Service CAPEC-552: Install Rootkit Install Rootkit CAPEC-556: Replace File Extension Handlers Replace File Extension Handlers CAPEC-558: Replace Trusted Executable Replace Trusted Executable CAPEC-562: Modify Shared File Modify Shared File CAPEC-563: Add Malicious File to Shared Webroot Add Malicious File to Shared Webroot CAPEC-564: Run Software at Logon Run Software at Logon CAPEC-578: Disable Security Software Disable Security Software

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2025-20335 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2025-20335 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Initial Analysis by [email protected]

    Jan. 05, 2026

    Action Type Old Value New Value
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:desk_phone_9841_firmware:*:*:*:*:*:*:*:* versions from (including) 3.0(1) up to (excluding) 3.3(1) OR cpe:2.3:h:cisco:desk_phone_9841:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:desk_phone_9851_firmware:*:*:*:*:*:*:*:* versions from (including) 3.0(1) up to (excluding) 3.3(1) OR cpe:2.3:h:cisco:desk_phone_9851:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:desk_phone_9861_firmware:*:*:*:*:*:*:*:* versions from (including) 3.0(1) up to (excluding) 3.3(1) OR cpe:2.3:h:cisco:desk_phone_9861:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:desk_phone_9871_firmware:*:*:*:*:*:*:*:* versions from (including) 3.0(1) up to (excluding) 3.3(1) OR cpe:2.3:h:cisco:desk_phone_9871:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_7811_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_7811_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_7811_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_7811:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_7821_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_7821_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_7821_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_7821:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_7841_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_7841_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_7841_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_7841:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_7861_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_7861_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_7861_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_7861:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8811_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8811_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8811_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8811:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8841_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8841_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8841_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8841:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8845_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8845_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8845_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8845:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8851_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8851_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8851_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8851:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8851nr_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8851nr_firmware:14.3(1):-:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8851nr_firmware:14.3(1):sr1:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8851nr:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8861_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8861_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8861_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8861:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8865_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 14.3(1) *cpe:2.3:o:cisco:ip_phone_8865_firmware:14.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8865_firmware:14.3(1):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8865:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:video_phone_8875_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 2.3(1) *cpe:2.3:o:cisco:video_phone_8875_firmware:2.3(1):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:video_phone_8875_firmware:2.3(1):-:*:*:*:*:*:* *cpe:2.3:o:cisco:video_phone_8875_firmware:*:*:*:*:*:*:*:* versions from (including) 3.0(1) up to (excluding) 3.3(1) OR cpe:2.3:h:cisco:video_phone_8875:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):sr1:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):sr2:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):sr4:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):sr5:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):sr6:*:*:*:*:*:* *cpe:2.3:o:cisco:ip_phone_8821_firmware:*:*:*:*:*:*:*:* versions up to (excluding) 11.0(6) *cpe:2.3:o:cisco:ip_phone_8821_firmware:11.0(6):-:*:*:*:*:*:* OR cpe:2.3:h:cisco:ip_phone_8821:-:*:*:*:*:*:*:*
    Added Reference Type Cisco Systems, Inc.: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-write-g3kcC5Df Types: Vendor Advisory
  • New CVE Received by [email protected]

    Sep. 03, 2025

    Action Type Old Value New Value
    Added Description 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.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
    Added CWE CWE-284
    Added Reference https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-write-g3kcC5Df
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.3
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact