TimescaleDB through 2.29.1, fixed in commit 517c13e, contains an out-of-bounds read vulnerability in the Gorilla compression reverse row iterator that allows authenticated attackers to cause a denial of service by storing a crafted compressed datum with an internally inconsistent BitArray. Attackers with DML access to a compressed hypertable can trigger an unsigned integer wraparound in the reverse iterator bucket index computation, causing a read beyond the end of the bucket array, resulting in a SIGSEGV crash that can be repeatedly triggered on each subsequent reverse-order scan.