EUVD-2025-21164
CVSS Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
4Description
A hidden remote support feature protected by a static secret in TOTOLINK N300RB firmware version 8.54 allows an authenticated attacker to execute arbitrary OS commands with root privileges.
Analysis
CVE-2025-52089 is a critical remote code execution vulnerability in TOTOLINK N300RB firmware version 8.54, where a hidden remote support feature protected only by a static secret allows authenticated attackers to execute arbitrary OS commands with root privileges. While the CVSS 3.1 score of 8.8 reflects high severity, the attack vector is adjacent network (AV:A), limiting widespread exploitation to network-adjacent attackers. The vulnerability has not been publicly confirmed as actively exploited or included in CISA's Known Exploited Vulnerabilities (KEV) catalog, but the simplistic authentication mechanism (static secret) and hidden feature design suggest high exploitability once discovered.
Technical Context
The vulnerability resides in a covert remote support functionality within the TOTOLINK N300RB router firmware (version 8.54), likely implemented as an undocumented service or management interface. The root cause is classified under CWE-306 (Missing Authentication), indicating the feature relies solely on a static, hardcoded secret rather than proper authentication mechanisms. This is compounded by security-through-obscurity: the feature's existence is not documented, making it discoverable only through reverse engineering or credential compromise. The vulnerability affects network-attached devices (CPE likely: cpe:2.3:h:totolink:n300rb:*:*:*:*:*:*:*:* or equivalent firmware CPE), which typically operate as residential or small-business gateway devices. The static secret authentication bypass, combined with OS command execution capability, suggests the feature may expose shell command injection or parameter tampering vulnerabilities in the management interface.
Affected Products
Specific affected product: TOTOLINK N300RB firmware version 8.54. CPE: cpe:2.3:o:totolink:n300rb_firmware:8.54:*:*:*:*:*:*:* (or hardware CPE cpe:2.3:h:totolink:n300rb:*:*:*:*:*:*:*:* with affected firmware versions). TOTOLINK is a lesser-known Chinese networking vendor; N300RB is a 300 Mbps WiFi router commonly deployed in emerging markets and as ISP equipment. The specificity to firmware version 8.54 suggests the vulnerability may have been patched in earlier or later versions; vendor advisories and patch release notes should be consulted to identify safe versions. No vendor security advisory URL was provided in the CVE data; users should check TOTOLINK's official support portal or security notifications for firmware update availability.
Remediation
Immediate remediation: (1) Update TOTOLINK N300RB firmware to the latest available version released after 8.54—check TOTOLINK's official firmware download page or contact ISP if device is ISP-managed; (2) If firmware update is unavailable, isolate the device from untrusted network segments (disable guest networks, restrict administrative access, implement network ACLs to limit device accessibility); (3) Change any default credentials and disable remote management features if accessible via user interface. Long-term: (1) Monitor TOTOLINK's security advisories and firmware release notes for patches addressing CVE-2025-52089; (2) Consider device replacement if vendor ceases support; (3) Implement network segmentation to restrict lateral movement if device is compromised (device on isolated IoT VLAN with egress filtering). Workarounds: No effective workaround exists without firmware update, given the static secret authentication and hidden feature design—the vulnerability is inherent to the firmware version.
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