MikroTik RouterOS up to 7.23.3/7.24.1 TFTP RRQ Builder TFTP RRQ builder function stack-based overflow

CVSS Meta Temp Score
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CTI Interest Score
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5.3$0-$5k1.32

Summaryinfo

A vulnerability described as critical has been identified in MikroTik RouterOS up to 7.23.3/7.24.1. The impacted element is the function TFTP RRQ builder function of the component TFTP RRQ Builder. The manipulation results in stack-based overflow. This vulnerability is cataloged as CVE-2026-89020. The attack may be launched remotely. There is no exploit available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in MikroTik RouterOS up to 7.23.3/7.24.1. It has been classified as critical. Affected is the function TFTP RRQ builder function of the component TFTP RRQ Builder. The manipulation with an unknown input leads to a stack-based overflow vulnerability. CWE is classifying the issue as CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). This is going to have an impact on availability. CVE summarizes:

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.

The advisory is available at mikrotik.com. This vulnerability is traded as CVE-2026-89020 since 09/10/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit.

Upgrading to version 7.23.4 or 7.24.2 eliminates this vulnerability.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

Vendor

Name

Version

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 5.4
VulDB Meta Temp Score: 5.3

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 4.3
CNA Vector (VulnCheck): 🔒

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Stack-based overflow
CWE: CWE-121 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: RouterOS 7.23.4/7.24.2

Timelineinfo

09/10/2026 CVE reserved
09/14/2026 +4 days Advisory disclosed
09/14/2026 +0 days VulDB entry created
09/14/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: mikrotik.com
Status: Confirmed

CVE: CVE-2026-89020 (🔒)
GCVE (CVE): GCVE-0-2026-89020
GCVE (VulDB): GCVE-100-403674

Entryinfo

Created: 09/14/2026 20:35
Changes: 09/14/2026 20:35 (77)
Complete: 🔍
Cache ID: 216::103

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