CVE-2026-102639: Signed to Unsigned Conversion Error

MobilityDB version 1.3.0 and earlier contains an out-of-bounds read vulnerability in the MEOS binary and library WKB deserialization logic that allows unprivileged database users to crash the PostgreSQL backend process by supplying a crafted WKB payload with a negative length field. The negative length value wraps to a large unsigned size_t due to missing signed validation, bypasses an overflow-unsafe pointer arithmetic bounds check in wkb_parse_state_check(), and causes memcpy() in text_from_wkb_state() to operate with a corrupted unbounded length, resulting in a remote denial-of-service condition affecting all sessions on the PostgreSQL instance.