CVE-2026-6475 | PostgreSQL pg_basebackup and pg_rewind can overwrite unrelated files of origin superuser choice

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.

Published: 2026-05-14 Last update: 2026-05-18 Assigner: f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 Source: f86ef6dc-4d3a-42ad-8f28-e6d5547a5007
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-6475 is rated Moderate Risk (40.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-6475

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-15 — 0.05% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-6475

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Weakness enumeration for CVE-2026-6475

GitHub Security Advisory for CVE-2026-6475

GHSA-7h2q-899j-9636 · Severity: high — Symlink following in PostgreSQL pg_basebackup plain format and in pg_rewind allows an origin...

OS Trackers for CVE-2026-6475

vendor priority summary link
debian not yet assigned CVE-2026-6475 not yet assigned priority: Debian including 4 source packages (postgresql-13, postgresql-15, postgresql-17, postgresql-18), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 4, open 1. https://security-tracker.debian.org/tracker/CVE-2026-6475
suse high CVE-2026-6475 severity important: SUSE including 176 source package names (libecpg6-17.10-3.27.1, libecpg6-18.4-150200.5.12.1, …), 773 product×package rows across 31 product lines (SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (31 product lines)): First Fixed 340, Fixed 269, Known Not Affected 164. https://www.suse.com/security/cve/CVE-2026-6475/
ubuntu medium CVE-2026-6475 medium priority: Ubuntu including 8 source packages (postgresql-10, postgresql-12, …), 44 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 28, needs-triage 7, ignored 4, released 4, deferred 1. https://ubuntu.com/security/CVE-2026-6475

Affected software / configurations for CVE-2026-6475

Vendor Product Version Raw CPE
postgresql postgresql < 14.23 cpe:2.3:a:postgresql:postgresql:*:*:*:*:*:*:*:*
postgresql postgresql >= 15.0, < 15.18 cpe:2.3:a:postgresql:postgresql:*:*:*:*:*:*:*:*
postgresql postgresql >= 16.0, < 16.14 cpe:2.3:a:postgresql:postgresql:*:*:*:*:*:*:*:*
postgresql postgresql >= 17.0, < 17.10 cpe:2.3:a:postgresql:postgresql:*:*:*:*:*:*:*:*
postgresql postgresql >= 18.0, < 18.4 cpe:2.3:a:postgresql:postgresql:*:*:*:*:*:*:*:*

References for CVE-2026-6475

cvelogic Threat Intelligence