How severe is CVE-2025-20335?

CVE-2025-20335 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2025-20335 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-20335?

CVE-2025-20335 primarily affects Cisco Desk Phone 9841 Firmware. In total, 47 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-20335?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-20335 have an EU (EUVD) identifier?

Yes. CVE-2025-20335 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-26614.

When was CVE-2025-20335 published?

CVE-2025-20335 was published on 2025-09-03 and last updated on 2026-06-17.

CVE-2025-20335

CVE-2025-20335 is a medium-severity vulnerability in Cisco Desk Phone 9841 Firmware with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-26614
Weakness: CWE-284
Affected product: Cisco Desk Phone 9841 Firmware
Published: 2025-09-03
Last modified: 2026-06-17

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.

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.
How severe is CVE-2025-20335?: CVE-2025-20335 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2025-20335 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-20335?: CVE-2025-20335 primarily affects Cisco Desk Phone 9841 Firmware. In total, 47 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-20335?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-20335 have an EU (EUVD) identifier?: Yes. CVE-2025-20335 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-26614.
When was CVE-2025-20335 published?: CVE-2025-20335 was published on 2025-09-03 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-write-g3kcC5Df

Affected products (47)

cpe:2.3:o:cisco:desk_phone_9841_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:desk_phone_9851_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:desk_phone_9861_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:desk_phone_9871_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7811_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7811_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7811_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7821_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7821_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7821_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7841_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7841_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7841_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7861_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7861_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_7861_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8811_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8811_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8811_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8841_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8841_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8841_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8845_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8845_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8845_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8851_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8851_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8851_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8851nr_firmware:*:*:*:*:*:*:*:*
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:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8861_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8861_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8861_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8865_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8865_firmware:14.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8865_firmware:14.3\(1\):sr1:*:*:*:*:*:*
cpe:2.3:o:cisco:video_phone_8875_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:video_phone_8875_firmware:2.3\(1\):-:*:*:*:*:*:*
cpe:2.3:o:cisco:video_phone_8875_firmware:2.3\(1\):sr1:*:*:*:*:*:*

More vulnerabilities in Cisco Desk Phone 9841 Firmware

CVE-2025-20350 — High (CVSS 7.5): A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video…
CVE-2025-20351 — Medium (CVSS 6.1): A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video…
CVE-2025-20336 — Medium (CVSS 5.3): A vulnerability in the directory permissions of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and…
CVE-2024-20445 — Medium (CVSS 5.3): A vulnerability in the web UI of Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video…
CVE-2025-20158 — Medium (CVSS 4.4): A vulnerability in the debug shell of Cisco Video Phone 8875 and Cisco Desk Phone 9800 Series could allow an…

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