CVE-2025-11371: Unpatched zero-day in Gladinet CentreStack, Triofox under attack

Gladinet CentreStack and Triofox, in their default installation and configuration, contain an unauthenticated local file inclusion flaw (CWE-552) that allows unintended disclosure of system files to remote attackers. The flaw requires no privileges or user interaction (CVSS 3.1: AV:N/PR:N/UI:N, 7.5 High), so any internet-facing deployment is directly reachable over the network. An attacker gains access to system files that should not be externally readable, and related reporting indicates active attacks have chained the flaw — including with Gladinet's hardcoded keys — toward unauthorized access, code execution, and deployment of remote access tools. All versions prior to and including 16.7.10368.56560 of both products are affected. Exploitation has been observed in the wild: the vulnerability was added to CISA's KEV on 2025-11-04 and carries a 92.1% EPSS probability of exploitation within 30 days.

Do: Upgrade CentreStack and Triofox to a release newer than 16.7.10368.56560, and apply vendor mitigations per CISA BOD 22-01 requirements (federal agencies must mitigate or discontinue use of affected versions). Until patched, restrict internet exposure of the service and review logs for suspicious unauthenticated requests, unexpected file reads, new accounts, or signs of follow-on compromise such as remote-access tool installation. The Huntress write-up referenced in this record provides exploitation context for detection guidance; no exploit code is required to confirm patch status.

Gladinet CentreStack (and, per CISA, the companion product Triofox) ships with a hard-coded ASP.NET machineKey in the portal's web.config, which is used to protect ViewState and similar serialized data. An attacker who knows this fixed key can craft a serialized payload and submit it to the network-facing portal, where server-side deserialization executes it, yielding unauthenticated remote code execution (CVSS 9.8, no privileges or user interaction required). Successful RCE gives attackers full control of the file-sharing server (high confidentiality, integrity and availability impact); public reporting indicates attackers have abused the flaw to gain unauthorized access and install remote access tools. Anyone running the affected CentreStack builds is exposed, with self-hosted deployments at SMBs and MSP-hosted environments the typical footprint. The flaw was exploited in the wild in March 2025, was added to CISA's Known Exploited Vulnerabilities catalog on 2025-04-08, and carries an EPSS of 94.3% (100th percentile).

Do: Upgrade CentreStack to 16.4.10315.56368 or later, and apply the equivalent vendor fix for Triofox; as an interim mitigation, administrators can delete the hard-coded machineKey defined in portal\web.config so it is regenerated. Because the flaw is actively exploited, review portals for signs of compromise (unexpected accounts, unfamiliar processes or remote access tools) and, for federal agencies, follow the applicable BOD 22-01 required actions.