CVE-2025-20335

MEDIUM
Published Sep 3, 2025 Modified Jan 5, 2026 CWE-284

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.

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CVSS v3.1 Score

5.3
MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Weakness Type (CWE)

CWE-284 CWE-284

Affected Products

Vendor Product
cisco desk_phone_9841_firmware
cisco desk_phone_9841
cisco desk_phone_9851_firmware
cisco desk_phone_9851
cisco desk_phone_9861_firmware
cisco desk_phone_9861
cisco desk_phone_9871_firmware
cisco desk_phone_9871
cisco ip_phone_7811_firmware
cisco ip_phone_7811_firmware
cisco ip_phone_7811_firmware
cisco ip_phone_7811
cisco ip_phone_7821_firmware
cisco ip_phone_7821_firmware
cisco ip_phone_7821_firmware
cisco ip_phone_7821
cisco ip_phone_7841_firmware
cisco ip_phone_7841_firmware
cisco ip_phone_7841_firmware
cisco ip_phone_7841
cisco ip_phone_7861_firmware
cisco ip_phone_7861_firmware
cisco ip_phone_7861_firmware
cisco ip_phone_7861
cisco ip_phone_8811_firmware
cisco ip_phone_8811_firmware
cisco ip_phone_8811_firmware
cisco ip_phone_8811
cisco ip_phone_8841_firmware
cisco ip_phone_8841_firmware
cisco ip_phone_8841_firmware
cisco ip_phone_8841
cisco ip_phone_8845_firmware
cisco ip_phone_8845_firmware
cisco ip_phone_8845_firmware
cisco ip_phone_8845
cisco ip_phone_8851_firmware
cisco ip_phone_8851_firmware
cisco ip_phone_8851_firmware
cisco ip_phone_8851
cisco ip_phone_8851nr_firmware
cisco ip_phone_8851nr_firmware
cisco ip_phone_8851nr_firmware
cisco ip_phone_8851nr
cisco ip_phone_8861_firmware
cisco ip_phone_8861_firmware
cisco ip_phone_8861_firmware
cisco ip_phone_8861
cisco ip_phone_8865_firmware
cisco ip_phone_8865_firmware
cisco ip_phone_8865_firmware
cisco ip_phone_8865
cisco video_phone_8875_firmware
cisco video_phone_8875_firmware
cisco video_phone_8875_firmware
cisco video_phone_8875_firmware
cisco video_phone_8875
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821_firmware
cisco ip_phone_8821

References

Frequently Asked Questions

What is CVE-2025-20335? +
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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2025-20335? +
CVE-2025-20335 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2025-20335? +
CVE-2025-20335 affects products from cisco, specifically: desk_phone_9841, desk_phone_9841_firmware, desk_phone_9851, desk_phone_9851_firmware, desk_phone_9861, desk_phone_9861_firmware, desk_phone_9871, desk_phone_9871_firmware, ip_phone_7811, ip_phone_7811_firmware, ip_phone_7821, ip_phone_7821_firmware, ip_phone_7841, ip_phone_7841_firmware, ip_phone_7861, ip_phone_7861_firmware, ip_phone_8811, ip_phone_8811_firmware, ip_phone_8821, ip_phone_8821_firmware, ip_phone_8841, ip_phone_8841_firmware, ip_phone_8845, ip_phone_8845_firmware, ip_phone_8851, ip_phone_8851_firmware, ip_phone_8851nr, ip_phone_8851nr_firmware, ip_phone_8861, ip_phone_8861_firmware, ip_phone_8865, ip_phone_8865_firmware, video_phone_8875, video_phone_8875_firmware. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-20335? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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