CVE-2026-103903
HighCVSS 8.8Exploitation Probability (EPSS)
Low risk34th percentile - higher than 34% of all known CVEs
Summary
An incorrect authorization vulnerability in the WinBox authentication flow of MikroTik RouterOS allows a remote authenticated attacker with low-privilege credentials to obtain the authorization policy of a different account, such as admin, without knowing the password.
Risk Assessment
A low-privilege user can gain full administrative session and escalate privileges, potentially leading to full router compromise.
Recommendation
Update MikroTik RouterOS to a patched version and restrict WinBox access to trusted users only.
Other vulnerabilities in MikroTik RouterOS
See all- CVE-2024-27686High
Mikrotik RouterOS versions 6.40.5 through 6.49.10 (fixed in 7) allow a remote attacker to cause a device crash via crafted packet data to the SMB service on TCP port 445.
- CVE-2026-67278Critical
MikroTik RouterOS (7.x) accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because the trust store includes an e=3 root CA, an attacker controlling or redirecting outbound TLS can use the root's public certificate to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. This also undermines RSA-based SSH authentication.
- CVE-2018-14847CriticalActively exploited
MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary files and remote authenticated attackers to write arbitrary files due to a directory traversal vulnerability in the WinBox interface.
- CVE-2018-7445CriticalActively exploited
A buffer overflow was found in the MikroTik RouterOS SMB service when processing NetBIOS session request messages. A remote attacker with access to the service can exploit this vulnerability to gain code execution on the system, and the overflow occurs before authentication, so an unauthenticated remote attacker can exploit it.
- CVE-2026-93345High
MikroTik RouterOS before 7.25beta4 contains an improper input validation vulnerability in the labelled-VPN NLRI iterators of the routing service. An unauthenticated on-path attacker can send a malformed MP_REACH_NLRI UPDATE message with a prefix-length value below the minimum valid for a labelled-VPN NLRI, which passes validation while describing a route with a negative-length address portion. The fix is carried only in 7.25beta4 (a development build); the current stable release 7.24.2 and the long-term release 7.23.5 both remain affected.
- CVE-2025-56566Medium
MikroTik firmware 7.19.4 stores sensitive authentication credentials and network state in cleartext within non-volatile storage. An attacker with physical access to the device can extract this material from an SPI flash dump without authenticating and without knowing the administrative password.
- CVE-2026-89028High
MikroTik RouterOS before 7.24 contains a heap memory corruption vulnerability in the userspace SMB daemon that allows remote attackers to corrupt adjacent heap memory by supplying a crafted uniPwdLen value in the SMB1 SessionSetupAndX handler. An attacker can send a malformed SMB1 request with a uniPwdLen field that triggers an integer underflow, causing the resulting value to be used as the copy length in a memory copy operation into a smaller heap buffer, corrupting adjacent heap memory.
- CVE-2026-89021Medium
MikroTik RouterOS before 7.24.2 contains a path traversal vulnerability in the container package OCI/tar image extraction. An attacker can write files outside the container root by supplying a crafted image with symlinks pointing to arbitrary paths. Via /container/add, this allows root-privileged file creation, directory creation, file deletion via overlayfs whiteout, and hardlink creation on the persistent data partition without starting the container. The 7.23.x long-term branch does not contain the fix.
- CVE-2026-89020Medium
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, allowing authenticated users to crash the mtget worker process by supplying a URL path of 507 bytes or more to the /tool fetch command.
- CVE-2026-14227Medium
A product with the MikroTik RouterOS API enabled is vulnerable to insufficient session expiration. Active sessions may retain their previous permission set after inactivity timeouts or user-group changes.
Original NVD description (English source)
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.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS