MikroTik RouterOS WinBox split-principal authentication bypass allows privilege escalation
CVSS score
8.7
EPSS probability
—
Risk score
0.9
Published
14 h ago
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Impact on My Inventory
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
0/2
Evidence confidence
%47
Short explanation
An incorrect authorization vulnerability exists in the WinBox authentication flow of MikroTik RouterOS. A remote authenticated low-privilege attacker can obtain an administrative session by verifying stage-one using their own account while supplying a target account in stage-two.
It enables a low-privilege user to gain a full administrative session without knowing the target account password and increase their own account privileges.
What should be done?
- Follow vendor advisories and changelogs
- Review the affected version range
- Apply vendor recommendations accordingly
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Chain of evidence and sources
MikroTik RouterOS WinBox kimlik doğrulama akışındaki yanlış yetkilendirme açığı, düşük yetkili bir saldırganın farklı bir hesabın yetki politikasını elde etmesine izin verir.
Saldırgan aşama bir EC-SRP doğrulamasını kendi hesabı üzerinden gerçekleştirirken, bağımsız olarak sağlanan aşama iki kullanıcı adı hedef hesabın ayrıcalıklarını kurmak için kullanılır.
Show the technical text from the sources
An incorrect authorization vulnerability in the WinBox authentication flow of MikroTik RouterOS allows a remote authenticated attacker with credentials for a low-privilege account permitted to use WinBox to obtain the authorization policy of a different existing account. The stage-one EC-SRP challenge and proof are verified using the attacker's account, while the independently supplied stage-two username is used to install the target account's privileges. By specifying a higher-privilege account such as admin, a low-privilege user can obtain a full administrative session without knowing the target account's password and can use that session to increase the privileges of the attacker's own account.
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CWE: CWE-863
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-103903 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | mikrotik | routeros | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 8.8 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CVE CNA |
| 8.8 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | NVD |
| 8.7 | CVSS V4_0 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | CVE CNA |
| 8.7 | CVSS V40 | HIGH | CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-103903 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-103903 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
SSH session privilege manipulation via a crafted username in Mikrotik RouterOS
Vulnerability in Mikrotik Routeros
Kernel memory disclosure and denial of service in MikroTik RouterOS btest service
Vulnerability in N/a
Vulnerability in N/a
SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS
Get this vulnerability through the API
Affected products, version ranges, exploitation status and patch information in a single request, with a free key.
curl -H "x-api-key: $DAYBREACH_API_KEY" \ "https://api.enginteksut.com.tr/api/v1/intel/cves/CVE-2026-103903"