CVE-2026-6475

Name	CVE-2026-6475
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-4646-1, DSA-6269-1, DSA-6270-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
postgresql-13 (PTS)	bullseye	13.16-0+deb11u1	vulnerable
	bullseye (security)	13.23-0+deb11u4	fixed
postgresql-15 (PTS)	bookworm	15.17-0+deb12u1	vulnerable
	bookworm (security)	15.18-0+deb12u1	fixed
postgresql-17 (PTS)	trixie	17.9-0+deb13u1	vulnerable
	trixie (security)	17.10-0+deb13u1	fixed
postgresql-18 (PTS)	forky, sid	18.4-1	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
postgresql-13	source	bullseye	13.23-0+deb11u4	DLA-4646-1
postgresql-13	source	(unstable)	(unfixed)
postgresql-15	source	bookworm	15.18-0+deb12u1	DSA-6269-1
postgresql-15	source	(unstable)	(unfixed)
postgresql-17	source	trixie	17.10-0+deb13u1	DSA-6270-1
postgresql-17	source	(unstable)	(unfixed)
postgresql-18	source	(unstable)	18.4-1

https://www.postgresql.org/about/news/postgresql-184-1710-1614-1518-and-1423-released-3297/