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TI-2026-60330 Aliases CVE-2026-89020GHSA-66qh-8rrp-pqjv

MikroTik RouterOS Stack Buffer Overflow via TFTP URL Path Leading to Privilege Escalation

Priority LOW 38CWE-121Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-121 and the CVSS impact.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00556 46th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed RouterOS (MikroTik): 6.49.21, 7.23.4, 7.24.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MikroTikRouterOS6.0.0 to before 6.49.21; 7.0.0 to before 7.23.4; 7.24.0 to before 7.24.26.49.21, 7.23.4, 7.24.2Patch availableCNA
  • RouterOS VendorMikroTik Affected 6.0.0 to before 6.49.21; 7.0.0 to before 7.23.4; 7.24.0 to before 7.24.2 Fixed in 6.49.21, 7.23.4, 7.24.2 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*——MikroTik
  • cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:* Versions — — ·MikroTik

Remediation

  • Fix · CNA RouterOS (MikroTik) Fixed in 6.49.21, 7.23.4, 7.24.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-89020
  2. 2026-10-03 Alias added: GHSA-66qh-8rrp-pqjv
  3. 2026-11-06 Title updated · CNA
  4. 2026-11-06 CVSS score changed · CNA
  5. 2026-11-06 Fix available: MikroTik/[email protected] · CNA
  6. 2026-11-06 3 new references · CNA

References

Exploit 1

Patch 3

Advisory 1

  • TI-2018-05369 A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS… KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-58872 SSH session privilege manipulation via a crafted username in Mikrotik RouterOS KEVCVSS 4.0CRITICAL 9.2
  • TI-2018-10669 MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary… KEVCVSS 3.1CRITICAL 9.1
  • TI-2026-47574 Kernel memory disclosure and denial of service in MikroTik RouterOS btest service KEVCVSS 4.0HIGH 8.8
  • TI-2026-47576 SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS KEVCVSS 4.0MEDIUM 6.9
  • TI-2022-22302 Out-of-bounds read in MicroTik RouterOS CVSS 3.1CRITICAL 9.8
See all 108 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences