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CVE-2026-20281

HIGHCVSS 7.5/10

Last modified

CVE-2026-20281 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 that are running Cisco Session Initiation Protocol (SIP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted HTTP packets to the device.

Description

A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 that are running Cisco Session Initiation Protocol (SIP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted HTTP packets to the device. A successful exploit could allow the attacker to cause the affected device to continuously consume memory, resulting in a DoS condition. A manual reboot of the device is required to recover from this condition. Note: For this vulnerability to be exploitable, the phone must be registered to Cisco Unified Communications Manager (Unified CM) and have Web Access enabled. Web Access is disabled by default.

Metrics

CVSS 3.1
7.5/10

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

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
CiscoCisco Session Initiation Protocol (SIP) Software12.1(1)SR1; 11.5(1); 10.3(2); 10.2(2); 10.3(1); 10.3(1)SR4; 11.0(1); 10.4(1)SR2 3rd Party; 11.7(1); 12.1(1); 11.0(0.7) MPP; 9.3(4) 3rd Party; 12.5(1)SR2; 10.2(1)SR1; 9.3(4)SR3 3rd Party; 10.2(1); 12.5(1); 10.3(1)SR2; 11-0-1MSR1-1; 10.4(1) 3rd Party; 12.5(1)SR1; 11.5(1)SR1; 10.1(1)SR2; 12.0(1)SR2; 12.6(1); 10.3(1.11) 3rd Party; 12.0(1); 12.0(1)SR1; 9.3(3); 12.5(1)SR3; 10.3(1)SR4b; 9.3(4)SR1 3rd Party; 10.3(1)SR5; 10.1(1.9); 10.3(1.9) 3rd Party; 9.3(4)SR2 3rd Party; 10.3(1)SR1; 10.3(1)SR3; 10.1(1)SR1; 12.0(1)SR3; 12.6(1)SR1; 12.7(1); 10.3(1)SR6; 12.8(1); 12.7(1)SR1; 11.0(2)SR1; 11.0(4); 11.0(2); 11.0(4)SR3; 11.0(5); 11.0(3)SR2; 11.0(3)SR4; 11.0(3)SR3; 11.0(2)SR2; 11.0(4)SR1; 11.0(5)SR3; 11.0(3); 11.0(5)SR2; 11.0(3)SR6; 11.0(5)SR1; 11.0(4)SR2; 11.0(3)SR1; 11.0(3)SR5; 11.0(6); 12.8(1)SR1; 12.8(1)SR2; 14.0(1); 14.0(1)SR1; 11.0(6)SR1; 10.3(1)SR7; 14.0(1)SR2; 14.1(1); 14.0(1)SR3; 11.0(6)SR2; 14.1(1)SR1; 14.1(1)SR2; 11.0(6)SR4; 14.2(1); 14.2(1)SR1; 11.0(6)SR5; 14.1(1)SR3; 14.2(1)SR2; 3.1(1); 3.0(1); 2.3(1); 2.3(1)SR1; 2.2(1); 2.1(1); 2.0(1); 14.2(1)SR3; 3.1(1)SR1; 14.3(1); 3.2(1); 14.3(1)SR1; 14.2(1)SR4; 3.3(1); 11.0(6)SR6; 14.3(1)SR2; 3.4(1); 14.3(1)SR3; 3.5(1); 11.0(6)SR7; 3.5(1)SR1; 14.4(1); 3.6(1); 4.0(1); 14.4(1)SR1; 4.1(1); 14.4(1)SR2; 4.1(1)SR1

References

Timeline

Published
Last Modified
Status
Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-20281?
A vulnerability in Cisco Desk Phone 9800 Series, Cisco IP Phone 7800 and 8800 Series, and Cisco Video Phone 8875 that are running Cisco Session Initiation Protocol (SIP) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper memory management when an affected device processes HTTP packets. An attacker could exploit this vulnerability by sending a continuous stream of crafted HTTP packets to the device. A successful exploit could allow the attacker to cause the affected device to continuously consume memory, resulting in a DoS condition. A manual reboot of the device is required to recover from this condition. Note: For this vulnerability to be exploitable, the phone must be registered to Cisco Unified Communications Manager (Unified CM) and have Web Access enabled. Web Access is disabled by default.
How severe is CVE-2026-20281?
CVE-2026-20281 has a CVSS score of 7.5/10 (HIGH severity).
How do I fix CVE-2026-20281?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST