psqlODBC row cache overflow when a later FETCH changes the column count

Summary

psqlODBC sizes its row cache from the column count of a cursor's first result, but recomputes the column count from each later FETCH reply without checking that it matches. A server not trusted under current SSL settings can answer a later FETCH with more columns and make the driver write tuple records past the end of the heap allocation. A keyset reply with fewer columns than the key fields also underflows the unsigned field count. This is reachable with UseDeclareFetch enabled. Versions before psqlODBC 18.00.0006 are affected.

Remediation

1. Inventory every PostgreSQL psqlODBC deployment, including staging.
2. Upgrade PostgreSQL psqlODBC to 18.00.0006.
3. Confirm the running version after the upgrade.

References

• Advisoryhttps://github.com/postgresql-interfaces/psqlodbc/security/advisories/GHSA-6rmx-9q62-4w6m