CVE-2026-20281— Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability
Quick assessment
Affected
Cisco Cisco Session Initiation Protocol (SIP) Software
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
以下是该漏洞描述的中文翻译： Cisco 桌面电话 9800 系列、Cisco IP 电话 7800 和 8800 系列，以及 Cisco 视频电话 8875，如果运行 Cisco 会话初始协议（SIP）软件，可能存在一个漏洞，可能允许未认证的远程攻击者导致受影响设备发生拒绝服务（DoS）状况。 该漏洞源于受影响设备在处理 HTTP 数据包时的内存管理不当。攻击者可以通过向设备发送持续的特制 HTTP 数据包流来利用此漏洞。成功利用该漏洞将使受影响设备持续消耗内存，从而导致拒绝服务状况。从该状况恢复需要手动重启设备
Possible ATT&CK Techniques 1 AI
T1999Affected Version Matrix 110
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| Cisco | Cisco Session Initiation Protocol (SIP) Software | 12.1(1)SR1 |
affected |
11.5(1) |
affected | ||
10.3(2) |
affected | ||
10.2(2) |
affected | ||
10.3(1) |
affected | ||
10.3(1)SR4 |
affected | ||
11.0(1) |
affected | ||
10.4(1)SR2 3rd Party |
affected | ||
| … +102 more rows | |||
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I. Basic Information for CVE-2026-20281
Vulnerability Information
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Vulnerability Title
Cisco Desk Phone 9800 Series, IP Phone 7800 and 8800 Series, and Video Phone 8875 with SIP Software Denial of Service Vulnerability
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
在移除最后引用时对内存的释放不恰当(内存泄露)
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| Cisco | Cisco Session Initiation Protocol (SIP) Software | 12.1(1)SR1 | - |
|
II. Public POCs for CVE-2026-20281
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-20281 (1)
Same Patch Batch · Cisco · 2026-09-02 · 11 CVEs total
| CVE-2026-20279 | 9.8 CRITICAL | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20274 | 9.8 CRITICAL | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20212 | 9.8 CRITICAL | Cisco Nexus 3000 and 9000 Series Switches Silicon One Hardware Abstraction Layer Remote Co |
| CVE-2026-20280 | 8.8 HIGH | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20278 | 8.8 HIGH | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20275 | 8.8 HIGH | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20276 | 8.6 HIGH | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20277 | 8.2 HIGH | Cisco IOS XR Software Security Hardening Release: September 2026 |
| CVE-2026-20355 | 5.9 MEDIUM | Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty |
| CVE-2026-20354 | 5.9 MEDIUM | Cisco Secure Email S/MIME Ciphertext Decryption Vulnerabilty |
IV. Related Vulnerabilities
Same product: Cisco Session Initiation Protocol (SIP) Software
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CVE-2025-20351
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Same vendor: Cisco
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Same weakness: CWE-401
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V. Comments for CVE-2026-20281
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