CVE-2026-6475
Symlink following in PostgreSQL pg_basebackup plain format and in pg_rewind allows an origin superuser to overwrite local files, e.g.
Impact
Symlink following in PostgreSQL pg_basebackup plain format and in pg_rewind allows an origin superuser to overwrite local files, e.g. /var/lib/postgres/.bashrc, that hijack the operating system account. It will remain the case that starting the server after these commands implicitly trusts the origin superuser, due to features like shared_preload_libraries. Hence, the attack has practical implications only if one takes relevant action between these commands and server start, like moving the files to a different VM or snapshotting the VM. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Postgresql | Postgresql | before 14.23 from 15.0 before 15.18 from 16.0 before 16.14 from 17.0 before 17.10 from 18.0 before 18.4 |