SOCFortress CoPilot EUVD-2026-114084

Requires an authenticated customer_user (customer-portal) account - the lowest-privilege role - on a CoPilot instance prior to 0.1.76; no admin or analyst rights are needed. The vulnerable route POST /api/agent_data_store/upload is exposed to this role by default (no special non-default configuration is required), and the only server-side check is that the uploaded filename is non-empty, with no bucket allow-list, no per-tenant prefix enforcement, no ownership check, and no content-type/extension validation. The limiting factor is that the attacker must hold valid portal credentials for at least one tenant and must know or guess target bucket/object keys (e.g. sysmon-configs/<customer_code>/sysmon_config.xml, copilot-case-report-templates/<name>, copilot-cases/<case_id>/<file>, velociraptor-artifacts/<agent_id>/<flow_id>/<file>); the sibling list, download, and delete routes remain admin/analyst-only, so only the upload write path is reachable.

This is a genuine near-term priority rather than a CVSS-inflated issue, but its reach is gated by authentication. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:H/A:L, base 8.5) describes a network-reachable, low-complexity write that requires a low-privilege authenticated account (PR:L - the customer_user portal role) and no user interaction, with a changed scope reflecting cross-tenant and downstream-endpoint impact and integrity as the dominant effect (I:H, A:L, C:N). The vuln.today decision label is 'this_week', consistent with a serious-but-not-emergency posture. No EPSS score and no SSVC decision values were supplied in the input, and the issue is NOT present in CISA KEV, so there is no evidence of active exploitation. However, a working proof-of-concept is published in the GHSA advisory and was confirmed live by the reporter against the official ghcr.io/socfortress/copilot-backend image, so exploitability is proven even though in-the-wild use is not. The main factor tempering raw severity is that an attacker must already hold valid customer-portal (customer_user) credentials for at least one tenant; this is the lowest-privilege role, but it is still authenticated access, so the flaw is a privileged-insider / compromised-tenant-credential risk, not a remote-unauthenticated one. Note the CVSS vector reports C:N despite the cross-tenant nature - this is consistent with the advisory, because only the write/upload path is exposed while list/download/delete remain admin/analyst-only, so the impact is integrity and availability, not disclosure.

An attacker holding customer_user portal credentials for a single tenant sends a crafted POST to /api/agent_data_store/upload specifying an arbitrary bucket_name and object_name, and overwrites another tenant's sysmon-configs/<customer_code>/sysmon_config.xml to blind endpoint telemetry, or plants a malicious DOCX/HTML file in copilot-case-report-templates that is later rendered server-side as a path to code execution. A working proof-of-concept demonstrating exactly these cross-tenant writes is published in the vendor's GHSA advisory and was confirmed live by the reporter. Because the vector is network, low-complexity, and needs only the lowest-privilege authenticated role, exploitation is straightforward once valid portal credentials are obtained.