The JupSOL program is built on the SPL stake pool program, which is considered one of the safest programs in the Solana ecosystem. It has undergone multiple audits and has securely managed over $1B in staked SOL for years without issues.
The program authority is secured by a multisig that includes members from Sanctum, Jupiter, Mango, marginfi, and Jito. Any changes to the program require approval through a majority vote from this multisig, preventing any single party from making unilateral changes. The Jupiter team plans to eventually freeze the program for additional security.