SQLite before 3.53.2 contains a heap-based buffer overflow vulnerability in the FTS5 full-text search extension that allows attackers to cause a crash or execute arbitrary code by supplying a crafted database with malicious continuation page metadata specifying a szLeaf value smaller than 4. Attackers can trigger an integer underflow in fts5ChunkIterate() causing an inflated remaining byte count during FTS5 MATCH query processing, leading to a heap buffer overflow of attacker-controlled data in applications compiled with SQLITE_ENABLE_FTS5.