CVE-2026-51603

HIGHCVSS 7.5/10EPSS 0.41%

Last modified

CVE-2026-51603 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.41% chance of exploitation in the next 30 days.

Description

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.

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

EPSS Probability
0.41%

33.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

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

VendorProductVersions
n/a

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-51603?
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.
How severe is CVE-2026-51603?
CVE-2026-51603 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.41% probability of exploitation in the next 30 days.
How do I fix CVE-2026-51603?
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