CVE-2025-8939: tenda ac20_firmware

Vulnerability summary

CVE-2025-8939 is a high (CVSS 9.0) vulnerability in tenda ac20_firmware. EPSS estimates a 0.94% chance of exploitation in the next 30 days, higher than 60.5% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 14-08-2025
   PublishedVulnerability first disclosed.
2. 15-08-2025
   Last modifiedVulnerability information updated.

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.

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferThe product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
• CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer.