CVE-2026-89020: MikroTik RouterOS · Stack-based Buffer Overflow
Affects MikroTik RouterOSSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium : upgrade to 7.24.2 or 7.23.4 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 7.24.2, 7.23.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 14 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade MikroTik RouterOS to 7.24.2 or 7.23.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| MikroTikRouterOS | Affected
| Fixed in
|
| MikroTikRouterOS | Affected
| Fixed in
|
AI-suggested
If you cannot patch yet, restrict access to authenticated users and monitor usage of the /tool fetch command with tftp:// URLs to mitigate potential exploitation.
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.
References
- mikrotik.com/supportsec/september-2026-vulnerability (opens in a new tab)
- vulncheck.com/advisories/mikrotik-routeros-stack-buffer-overflow-via-tftp-url-path (opens in a new tab)
- forum.mikrotik.com/t/7-24-2-stable-is-released/272800 (opens in a new tab)
- forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 (opens in a new tab)