CVE-2021-31755 Tenda AC11 Router: memory-safety flaw
In plain words: The program mishandles the memory it uses to keep track of data. A specially made input can scramble that memory. Usually lets an attacker crash the program or run their own code with its permissions.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2021
What to do
- Install Tenda's security update for AC11 Router. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Turn on automatic firmware updates and replace gear the maker no longer supports.
- Change default passwords and switch off remote administration and features you do not use.
- Do not put storage boxes or cameras directly on the internet — use the maker's app or a VPN.
Who is affected
Could reach you. This one is aimed at devices or apps of the kind people own.
What's at risk: Taken over in bulk to join botnets, used to watch your traffic, or — for storage boxes — locked by ransomware.
The details
- Official name
- Tenda AC11 Router Stack Buffer Overflow Vulnerability
- Product
- Tenda AC11 Router
- CISA description
- Tenda AC11 devices contain a stack buffer overflow vulnerability in /goform/setmac which allows attackers to execute code via a crafted post request.
- Type of flaw
- Memory-safety flaw (CWE-787)
- Confirmed exploited
- Nov 3, 2021
- US federal patch deadline
- Nov 17, 2021
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Answering about CVE-2021-31755 ·
Questions about CVE-2021-31755
Is CVE-2021-31755 being exploited?
Yes. CISA added CVE-2021-31755 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks.
How do I fix CVE-2021-31755?
Install Tenda's security update for AC11 Router. If no update exists, follow the vendor's workaround or stop using the product until one ships. Turn on automatic firmware updates and replace gear the maker no longer supports.
Am I affected by CVE-2021-31755?
Only if you use Tenda AC11 Router. This one is aimed at devices or apps of the kind people own.