جزئیات آسیب‌پذیری

MikroTik RouterOS before 7.23.4 (long-term) and 7.24.2 (stable) contains a stack-based buffer overflow vulnerability in the mtget binary's TFTP RRQ builder function that allows authenticated users to crash the mtget worker process by supplying a URL path of 507 bytes or more to the /tool fetch command; the first write outside the 528-byte buffer occurs at 505 bytes. Attackers can trigger the overflow by issuing a fetch command with a crafted tftp:// URL path, which causes an unbounded rep movsb instruction to overwrite saved registers at a deterministic offset, crashing the process without requiring a reachable TFTP server or elevated privileges beyond read-only group membership. On older RouterOS versions, this overflow is not limited to crashing the process: the deterministic overwrite of saved registers is exploitable to achieve persistent privilege escalation on the device. On versions with intact exploit mitigations, the impact is limited to a crash of the mtget worker process.

• https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 patchrelease-notes
• https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 release-notespatch
• https://www.vulncheck.com/advisories/mikrotik-routeros-stack-buffer-overflow-via-tftp-url-path third-party-advisory
• https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 release-notespatch
• https://mikrotik.com/supportsec/cve-2026-89020/ vendor-advisory
• https://gitlab.com/sys65535/CVE-2026-89020-privesc-research technical-descriptionexploit