Medium severity · published Sep 14, 2026
CVE-2026-89020
MikroTik RouterOS Stack Buffer Overflow via TFTP URL Path
4.3
CVSS
0.5%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 42% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RO
RouterOS · MikroTik
before 7.23.4; 7.24.0 before 7.24.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-89020
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-89020
patch
https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800
release-notes
https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
third-party-advisory
https://www.vulncheck.com/advisories/mikrotik-routeros-stack-buffer-overflow-via-tftp-url-path
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