CVE-2026-51600
HighCVSS 7.5Exploitation Probability (EPSS)
Low risk32th percentile - higher than 32% of all known CVEs
Summary
Tenda CP3 V3.0 firmware V31.1.9.91 fails to validate the Content-Length header in RTSP requests (DESCRIBE, SETUP, PLAY). When a request includes this header without a body, the RTSP parser enters a persistent body-awaiting state, permanently blocking the TCP connection. An unauthenticated remote attacker can exploit this to exhaust TCP resources and cause a denial-of-service condition.
Risk Assessment
The risk is a remote unauthenticated DoS attack that can render the device unavailable, potentially disrupting video surveillance operations.
Recommendation
Immediately update the Tenda CP3 V3.0 firmware to the latest version that fixes the Content-Length header validation. If no update is available, restrict access to RTSP ports (default 554) to trusted networks only.
Other vulnerabilities in Tenda CP3
See all- CVE-2026-51606High
An improper input handling vulnerability in the RTSP service of Tenda CP3 V3.0 (firmware V31.1.9.91) causes the device to abruptly terminate the TCP connection with a RST packet when a request containing an oversized field value is received, without returning any RFC 2326-compliant error response. This behavior affects the request-line URL field and header field values across multiple RTSP request types.
- CVE-2026-51605High
A stack-based buffer overflow vulnerability in the RTSP service of Tenda CP3 V3.0 (firmware V31.1.9.991) allows an unauthenticated remote attacker to cause a denial of service via a crafted TEARDOWN request.
- CVE-2026-51604High
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 PLAY request.
- CVE-2026-51603High
A stack-based buffer overflow vulnerability exists in the RTSP service of Tenda CP3 V3.0 (firmware V31.1.9.91). An unauthenticated remote attacker can cause a denial of service by sending a crafted second SETUP request, crashing the RTSP service.
- CVE-2026-51602High
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 SETUP request. The second-stage URL parser fails to validate the URL length, enabling an attacker to bypass first-stage validation and trigger a stack buffer overflow, causing an immediate crash of the RTSP service and making the device inaccessible to all clients on the local network.
- CVE-2026-51601High
Tenda CP3 V3.0 firmware V31.1.9.91 contains a stack-based buffer overflow in the RTSP service. The device fails to validate the length of the clock= value in the Range header field when processing a PLAY request, which can cause the service to crash.
Original NVD description (English source)
Tenda CP3 V3.0 firmware V31.1.9.91 does not validate the Content-Length header field in RTSP requests (including DESCRIBE, SETUP, and PLAY methods). When a request carrying a Content-Length header is received without a corresponding message body, the RTSP parser enters a persistent body-awaiting state, causing the affected TCP connection to become permanently non-functional. The device does not actively close the connection, resulting in a TCP resource leak. This issue can be exploited by an unauthenticated remote attacker to cause a denial-of-service condition.