CVE-2025-15255
Published: 30 December 2025
Summary
CVE-2025-15255 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Tenda W6-S Firmware. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 33.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Flaw remediation requires applying vendor patches or updates to fix the stack-based buffer overflow in the httpd R7websSsecurityHandler component.
Information input validation enforces proper bounds checking on the Cookie argument to prevent the buffer overflow exploitation.
Memory protection mechanisms like stack canaries, ASLR, and DEP mitigate successful exploitation of the stack-based buffer overflow.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in the public-facing httpd web server of the Tenda W6-S router, exploitable remotely via manipulated Cookie header without authentication or privileges, directly enabling arbitrary code execution through exploitation of a public-facing application.
NVD Description
A vulnerability was determined in Tenda W6-S 1.0.0.4(510). This impacts an unknown function of the file /bin/httpd of the component R7websSsecurityHandler. Executing a manipulation of the argument Cookie can lead to stack-based buffer overflow. The attack may be launched remotely.…
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The exploit has been publicly disclosed and may be utilized.
Deeper analysisAI
CVE-2025-15255 is a stack-based buffer overflow vulnerability affecting the Tenda W6-S router in version 1.0.0.4(510). The flaw resides in an unknown function of the /bin/httpd binary, specifically within the R7websSsecurityHandler component. It stems from improper handling of the Cookie argument, as classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-121 (Stack-based Buffer Overflow).
The vulnerability enables remote exploitation over the network with low complexity, requiring no privileges, authentication, or user interaction (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H, base score 9.8). An attacker can manipulate the Cookie argument to trigger the overflow, potentially achieving arbitrary code execution and full compromise of the affected device, including high impacts to confidentiality, integrity, and availability.
Advisories from VulDB (ctiid.338645, id.338645, submit.725500) and a GitHub repository (dwBruijn/CVEs/blob/main/Tenda/R7WebsSecurityHandler.md) provide further details on the issue. The Tenda vendor website (tenda.com.cn) is referenced for potential updates, though no specific patches are detailed in the disclosure.
The exploit has been publicly disclosed and may be utilized, increasing the risk for unpatched Tenda W6-S devices exposed to the internet.
Details
- CWE(s)