KMT-2024-BLG-0404L (also known as OGLE-2024-BLG-0378L) is a red dwarf with a mass of 0.09 solar masses, located in the direction of the Galactic Bulge at a distance of 23,510 light-years, or approximately 7,210 parsecs, in the constellation Sagittarius.
Around the star KMT-2024-BLG-0404L, two planetary-mass objects were discovered in 2025 using the gravitational microlensing method. The first component, designated KMT-2024-BLG-0404Lb, is an exoplanet with a mass of 17.3 Earth masses and a projected separation of 0.34 astronomical units. The second component of the system, designated KMT-2024-BLG-0404Lc, is a brown dwarf with a mass of 26 Jupiter masses. The projected separation between the star and the brown dwarf is 0.85 astronomical units from the star. To ensure dynamical stability in the system, the planet should orbit only one of the host stars, and the separation between the binary components must be considerably greater than the distance from the planet to its host
Based on the estimated masses of the lens components, the system is identified as a planetary system in which a Neptune-mass planet orbits within a binary consisting of a late M dwarf and a brown dwarf.