Unauthenticated code execution via setmac stack overflow
Published May 7, 2021 · Updated Oct 21, 2025
Stack buffer overflow in the Tenda AC11 setmac handler through firmware 02.03.01.104_CN allows remote attackers to execute code. The /goform/setmac handler processes attacker-controlled POST data without enforcing the destination stack buffer's bounds. No authentication or user interaction is required, and successful memory corruption grants code execution with the router service's privileges.
Summary
What happened
Stack buffer overflow in the Tenda AC11 setmac handler through firmware 02.03.01.104_CN allows remote attackers to execute code. The /goform/setmac handler processes attacker-controlled POST data without enforcing the destination stack buffer's bounds. No authentication or user interaction is required, and successful memory corruption grants code execution with the router service's privileges.
The record
- CVE
- CVE-2021-31755
- Published
- May 7, 2021
- Updated
- Oct 21, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 7, 2021CVE publishedPublication date reported by the CVE source.
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
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.
View daily counts
| Reporting day | Unique IPs |
|---|---|
| Sep 10, 2026 | 5 |
| Sep 11, 2026 | 1 |
| Sep 12, 2026 | 1 |
| Sep 13, 2026 | 1 |
| Sep 14, 2026 | 1 |
| Sep 15, 2026 | Unavailable |
| Sep 16, 2026 | 1 |
Public exploit references
No public exploit references are available in this record.
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Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog listingknown exploited catalog
Technologies
Your stack
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Your stack
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