CVE-2025-9791: tenda ac20_firmware

Vulnerability summary

CVE-2025-9791 is a critical (CVSS 9.8) vulnerability in tenda ac20_firmware. EPSS estimates a 0.85% chance of exploitation in the next 30 days, higher than 57.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 01-09-2025
   PublishedVulnerability first disclosed.
2. 02-09-2025
   Last modifiedVulnerability information updated.

Description

A weakness has been identified in Tenda AC20 16.03.08.05. This vulnerability affects unknown code of the file /goform/fromAdvSetMacMtuWan. This manipulation of the argument wanMTU causes stack-based buffer overflow. Remote exploitation of the attack is possible. The exploit has been made available to the public and could be exploited.

• 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-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
• CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.