Authenticated root code execution via unchecked list copy
Published Feb 21, 2026 · Updated Feb 21, 2026
Stack-based buffer overflow in Tenda A21 1.0.0.0 allows remote authenticated users to execute code via a crafted list parameter. The fromSetIpMacBind handler copies the HTTP list value with strcpy into a 128-byte stack buffer and later passes parsed data to unsafe sprintf calls. Low-privileged management access is required; an oversized request can crash httpd, while return-address control enables root code execution.
Summary
What happened
Stack-based buffer overflow in Tenda A21 1.0.0.0 allows remote authenticated users to execute code via a crafted list parameter. The fromSetIpMacBind handler copies the HTTP list value with strcpy into a 128-byte stack buffer and later passes parsed data to unsafe sprintf calls. Low-privileged management access is required; an oversized request can crash httpd, while return-address control enables root code execution.
The record
- CVE
- CVE-2026-2871
- Published
- Feb 21, 2026
- Updated
- Feb 21, 2026
- Vendor
- Shenzhen Tenda Technology Co., Ltd.
- Product
- A21
- Classifications
- CWE-121, CWE-119, T1190
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 21, 2026CVE publishedPublication date reported by the CVE source.
- Feb 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=1.0.0.0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Oversized list parameter crash proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo