Executive brief
A stack-based buffer overflow vulnerability exists in the D-Link DIR-868L wireless router's web authentication handler that can be exploited remotely without authentication. An attacker can send a specially crafted request with an oversized user ID parameter to crash the router's web server or potentially execute arbitrary code, leading to complete device compromise or denial of service.
Technical details
The vulnerability is a classic stack-based buffer overflow in the strcpy function within the /webfa_authentication.cgi authentication handler component. An unauthenticated remote attacker can manipulate the "id" URL parameter with a 1864-byte value to overflow the stack buffer, overwriting the saved return address and achieving return-address control. The PoC demonstrates that 1860 filler bytes plus a 4-byte marker triggers a crash at the function epilogue, confirming control of the instruction pointer.
Affected products
- D-Link DIR-868L 2.01b05
Timeline
- 2026-09-20: disclosed: Vulnerability publicly disclosed with proof-of-concept exploit
- 2026-09-20: advisory: CVE-2026-94089 assigned