An internal aggregation expression in MongoDB Server was incorrectly registered as accessible to any authenticated user rather than being restricted to internal cluster operations. By crafting a malformed index specification within this expression, an authenticated user with read-only privileges could trigger an assertion failure in the index key generation code path. In certain build configurations, this assertion failure results in termination of the mongod process, causing a denial of service to all connected clients.
Published: 2026-09-08
Updated: 2026-09-08
Base Score: 4.9
Vector: CVSS2#AV:N/AC:H/Au:S/C:N/I:N/A:C
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
Severity: Medium
Base Score: 6
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00255