PostgreSQL pg_basebackup and pg_rewind can overwrite unrelated files of origin superuser choice

Summary

CVECVE-2026-6475
StatePUBLISHED
AssignerPostgreSQL
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-14 14:16:25 UTC
Updated2026-05-18 15:02:12 UTC
DescriptionSymlink 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.

Risk And Classification

Primary CVSS: v3.1 8.8 HIGH from f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS: 0.000490000 probability, percentile 0.152790000 (date 2026-05-25)

Problem Types: CWE-61 | CWE-61 UNIX Symbolic Link (Symlink) Following


VersionSourceTypeScoreSeverityVector
3.1f86ef6dc-4d3a-42ad-8f28-e6d5547a5007Secondary8.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNACVSS8.8HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Postgresql Postgresql All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na PostgreSQL affected 18 18.4 rpm Not specified
CNA Na PostgreSQL affected 17 17.10 rpm Not specified
CNA Na PostgreSQL affected 16 16.14 rpm Not specified
CNA Na PostgreSQL affected 15 15.18 rpm Not specified
CNA Na PostgreSQL affected 14.23 rpm Not specified

References

ReferenceSourceLinkTags
www.postgresql.org/support/security/CVE-2026-6475 f86ef6dc-4d3a-42ad-8f28-e6d5547a5007 www.postgresql.org Patch, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: The PostgreSQL project thanks Valery Gubanov, XlabAI Team of Tencent Xuanwu Lab, Atuin Automated Vulnerability Discovery Engine, Zhanpeng Liu (pkugenuine(at)gmail(dot)com), Guannan Wang (wgnbuaa(at)gmail(dot)com), and Guancheng Li (lgcpku(at)gmail(dot)com) for reporting this problem. (en)

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