How severe is CVE-2025-20350?

CVE-2025-20350 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2025-20350 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-20350?

CVE-2025-20350 primarily affects Cisco Desk Phone 9871 Firmware. In total, 67 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-20350?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-20350 have an EU (EUVD) identifier?

Yes. CVE-2025-20350 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34667.

When was CVE-2025-20350 published?

CVE-2025-20350 was published on 2025-10-15 and last updated on 2026-06-17.

CVE-2025-20350

CVE-2025-20350 is a high-severity vulnerability in Cisco Desk Phone 9871 Firmware with a CVSS 3.x base score of 7.5. 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-121.

Key facts

Severity: High (CVSS 3.x base score 7.5)
EPSS exploit prediction: 0% (36th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-34667
Weakness: CWE-121
Affected product: Cisco Desk Phone 9871 Firmware
Published: 2025-10-15
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2025-20350?: 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.
How severe is CVE-2025-20350?: CVE-2025-20350 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2025-20350 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (36th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-20350?: CVE-2025-20350 primarily affects Cisco Desk Phone 9871 Firmware. In total, 67 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-20350?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-20350 have an EU (EUVD) identifier?: Yes. CVE-2025-20350 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-34667.
When was CVE-2025-20350 published?: CVE-2025-20350 was published on 2025-10-15 and last updated on 2026-06-17.

References

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-phone-dos-FPyjLV7A

Affected products (67)

cpe:2.3:o:cisco:desk_phone_9871_firmware:*:*:*:*:*:*:*:*
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: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: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_8832_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8832_firmware:14.3\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:ip_phone_8832_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_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: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:*:*:*:*:*:*

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