CVE-2026-3678: Tenda FH451 AdvSetWan sub_3C434 stack-based overflow

Vulnerability summary

CVE-2026-3678 is a high (CVSS 9.0) vulnerability in tenda fh451_firmware. EPSS estimates a 1.02% chance of exploitation in the next 30 days, higher than 62.9% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 07-03-2026
   PublishedVulnerability first disclosed.
2. 11-03-2026
   Last modifiedVulnerability information updated.

Description

A vulnerability was determined in Tenda FH451 1.0.0.9. Affected is the function sub_3C434 of the file /goform/AdvSetWan. This manipulation of the argument wanmode/PPPOEPassword causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit has been publicly disclosed and may be utilized.

• 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).