Integer underflow in PostgreSQL ECPG allows a database server administrator to achieve temporary denial of service against the ECPG client via sending a bytea value lacking the mandatory prefix. The client overwrites a huge memory region with bytes outside attacker knowledge or control. This typically yields a simple SIGSEGV, but rare cases might achieve client-specific integrity impact via the write. Versions before PostgreSQL 18.5, 17.11, 16.15, 15.19, and 14.24 are affected.
Weakness
The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.