The Kabrel system was an uninhabited binary star system with two planets, located in Federation space near the Cardassian border. The binary stars in the system generate a great deal of ionic interference, discouraging settlement.

In 2374, the Dominion surreptitiously attempted to acquire the Kabrel system in the re-drawn border they proposed to the Federation during the short-lived peace talks following Operation Return. Their purpose was to gain control of Kabrel I, which represented a potentially unlimited source of ketracel-white. Doctor Julian Bashir and four other genetically engineered Humans advised the Federation to cede the Kabrel system to the Dominion, to forestall an immediate full-scale offensive. (DS9: "Statistical Probabilities")

This system was only mentioned in dialogue.
Ronald D. Moore commented: "The talks failed and [Kabrel] did not change hands." (AOL chat, 1998)
According to Stellar Cartography: The Starfleet Reference Library ("Federation Historical Highlights, 2161-2385"), the Kabrel system was located in the Alpha Quadrant. This binary system consisted of a G-class star and K-class star. In the late 24th century, it was an independent system.