AZL-113795: CVE-2026-16240 affecting package postgresql 16.15-1

Use of externally-controlled format string in PostgreSQL pgbasebackup allows an attacker having already compromised a server to achieve disclosure from pgbasebackup memory, via backup manifest bytes. The vulnerability does not return the improperly-read bytes back to the attacker's server, so a successful attack would need separate implementation-specific secrets for that. Integrity impact is unlikely; in particular, the applicable formatter does not support %n. Versions before PostgreSQL 18.7, 17.12, 16.16, 15.20, and 14.25 are affected.