This advisory covers several important security fixes for PostgreSQL 16 in Red Hat Enterprise Linux 9.4 and 10. The addressed vulnerabilities include CVE-2026-6475 (operating system account hijack via symlink following in pg_basebackup and pg_rewind), CVE-2026-6477 (buffer overflow in libpq allowing server superuser to overwrite client stack memory), CVE-2026-6478 (credential recovery via covert timing channel in MD5 password comparison), and CVE-2026-6473 (integer overflow causing undersized allocation and out-of-bounds write). These vulnerabilities affect both client and server components and pose risks including privilege escalation and credential exposure. Red Hat has released updated packages to remediate these issues.

The vulnerabilities could allow an attacker to hijack operating system accounts via symlink attacks, cause buffer overflows leading to memory corruption by a server superuser, recover credentials through timing side-channels, and trigger out-of-bounds memory writes due to integer overflow. These issues can compromise system integrity, confidentiality, and availability if exploited. The advisory rates the security impact as Important (high severity). No known exploits in the wild have been reported at the time of this advisory.

Red Hat has released official security updates for PostgreSQL 16 on Red Hat Enterprise Linux 9.4 and 10 that address these vulnerabilities. Users should apply the updated packages as detailed in the Red Hat advisories RHSA-2026:26524 and RHSA-2026:27743. Instructions for applying these updates are available at https://access.redhat.com/articles/11258. Applying these updates will remediate the vulnerabilities. No additional mitigation steps are indicated by the vendor.