Tenda CP3 V3.0 31.1.9.91 RTSP Service URL stack-based overflow

Summaryinfo

A vulnerability identified as critical has been detected in Tenda CP3 V3.0 31.1.9.91. This affects an unknown function of the component RTSP Service. Performing a manipulation of the argument URL results in stack-based overflow. This vulnerability was named CVE-2026-51603. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability classified as critical has been found in Tenda CP3 V3.0 31.1.9.91. This affects some unknown functionality of the component RTSP Service. The manipulation of the argument URL with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). This is going to have an impact on availability. The summary by CVE is:

A stack-based buffer overflow vulnerability in the RTSP service of Tenda CP3 V3.0 (firmware V31.1.9.91) allows an unauthenticated remote attacker to cause a denial of service via a crafted second SETUP request. After completing the OPTIONS, DESCRIBE, and a legitimate first SETUP request to obtain a valid session ID, the RTSP service's second-stage URL routing parser fails to validate the length of the URL field in the subsequent SETUP request. By supplying a URL consisting of exactly four consecutive repetitions of a valid RTSP URL, an attacker can bypass first-stage format validation and trigger a stack buffer overflow, causing an immediate crash of the RTSP service process and rendering the device inaccessible to all clients on the local network.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-51603 since 06/08/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/09/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Type

• Router Operating System

Vendor

• Tenda

Name

• CP3 V3.0

Version

• 31.1.9.91

License

• commercial

Website

• Vendor: https://www.tenda.com.cn/

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