libspatialite through 5.1.0 contains an integer overflow vulnerability in the WKB point and vertex count size guard of ParseWkbLine and related parsers in gg_wkb.c, allowing out-of-bounds reads. Attackers can supply a crafted geometry BLOB with a large point count, for example in a SpatiaLite database file, to crash the process or corrupt heap memory on 32-bit builds.