High severity · published Aug 14, 2025
CVE-2025-8939
Tenda AC20 WifiGuestSet buffer overflow
8.8
CVSS
0.9%
EPSS
No
On KEV
Description
A vulnerability was determined in Tenda AC20 up to 16.03.08.12. Affected is an unknown function of the file /goform/WifiGuestSet. The manipulation of the argument shareSpeed leads to buffer overflow. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 61% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
AC20 · Tenda
16.03.08.0; 16.03.08.1; 16.03.08.2; 16.03.08.3; 16.03.08.4; 16.03.08.5; +7 more · source: vendor
AF
Ac20 Firmware · Tenda
16.03.08.0 through 16.03.08.12 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-8939
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-8939
Exploit
https://github.com/lin-3-start/lin-cve/blob/main/Tenda%20AC20/Tenda%20AC20.md
Exploit
https://github.com/lin-3-start/lin-cve/blob/main/Tenda%20AC20/Tenda%20AC20.md#3-poc
Permissions Required
https://vuldb.com/?ctiid.319902
Third Party Advisory
https://vuldb.com/?id.319902
Third Party Advisory
https://vuldb.com/?submit.631829
Product
https://www.tenda.com.cn/
More from AC20
9.8
CVE-2025-9791
Tenda AC20 fromAdvSetMacMtuWan stack-based overflow
9.8
CVE-2025-9090
Tenda AC20 Telnet Service telnet websFormDefine command injection
9.8
CVE-2025-9089
Tenda AC20 SetIpMacBind sub_48E628 stack-based overflow
9.8
CVE-2025-9088
Tenda AC20 formSetVirtualSer save_virtualser_data stack-based overflow
9.8
CVE-2025-9087
Tenda AC20 SetNetControlList Endpoint set_qosMib_list stack-based overflow