Authenticated code execution via unbounded sprintf
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 devName parameter. The set_device_name function passes the request-derived devName string to sprintf, which writes it into the 256-byte mib_vlaue stack buffer without a bounds check. Access to the MAC filtering endpoint requires low privileges; the published proof of concept demonstrates an httpd crash, while return-address corruption enables 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 devName parameter. The set_device_name function passes the request-derived devName string to sprintf, which writes it into the 256-byte mib_vlaue stack buffer without a bounds check. Access to the MAC filtering endpoint requires low privileges; the published proof of concept demonstrates an httpd crash, while return-address corruption enables code execution.
The record
- CVE
- CVE-2026-2872
- 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
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Is a vulnerable build present?
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- 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
- Tenda A21 setBlackRule Python proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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