MongoDB Database Tools EUVD-2026-116027

Exploitation requires all of the following concrete preconditions: (1) the attacker has authenticated access (PR:L) sufficient to modify a GridFS file's stored filename metadata field and sets it to '-'; (2) a higher-privileged operator subsequently retrieves that specific file using mongofiles get_id WITHOUT passing --local, so the attacker-controlled stored filename is used as the output destination and contents are written to standard output; and (3) that standard output is redirected or captured to a location the lower-privileged attacker can read. Limiting factors that reduce realistic risk: the privileged operator's retrieval is a required out-of-band action the attacker does not control (hence AT:P/UI:P), the operator must omit the --local destination (a non-default/incidental invocation), the attacker needs prior authenticated metadata-write access, and the output must be captured somewhere attacker-accessible. Only MongoDB Database Tools versions 3.1.4 through before 100.20.1 are affected.

This is a medium-severity information-disclosure issue (CVSS 4.0 base 5.9; note the input supplies a CVSS 4.0 vector, not 3.1) whose real-world risk is substantially lower than the raw number suggests because exploitation is heavily conditional. The 4.0 vector AV:N/AC:L/AT:P/PR:L/UI:P/VC:H/VI:N/VA:N shows a network-reachable but authenticated (PR:L) attacker, an attack requirement beyond attacker control (AT:P), and passive user interaction (UI:P) - meaning the attacker cannot complete the attack alone. The vuln.today Decision label is 'this_month' rather than 'act_now' or 'emergency', which is consistent with no CISA KEV listing, no EPSS probability supplied in the input, and no exploit code referenced. The single reference is MongoDB's own CHANGELOG, so there is no public exploit identified at time of analysis. The confidentiality-only impact (VC:H, with VI/VA/SC/SI/SA all N) is real but narrow: it discloses GridFS content to a user who already has authenticated metadata-write access, and only when a more-privileged operator independently triggers the retrieval and the captured output lands somewhere the attacker can read. This profile points to a targeted, opportunistic weakness rather than a widespread or automatable threat - prioritize it as routine patching, not an emergency.

An authenticated user with write access to GridFS file metadata changes a stored file's filename to '-'. Later, a higher-privileged operator runs a mongofiles get_id retrieval for that file without specifying --local, so the stored '-' is used as the output destination and the file contents are written to standard output instead of a local file. If that standard output has been redirected or captured somewhere the lower-privileged user can read, they obtain GridFS content they could not otherwise access. No public exploit identified at time of analysis.