PostgreSQL psql \unrestrict lets superuser of pg_dump origin server execute arbitrary code in psql client
CVE-2026-18408

8.8HIGH

Key Information:

Status
Postgresql
Vendor
CVE Published:
13 August 2026

What is CVE-2026-18408?

Untrusted data inclusion in pg_dump in PostgreSQL allows a malicious superuser of the origin server to inject arbitrary code for restore-time execution as the client operating system account running psql to restore the dump, via psql \restrict meta-command input expansion. The fix for CVE-2025-8714 introduced \restrict and \unrestrict to block this attack, but \unrestrict itself was sufficient for an attack. pg_dumpall is also affected. pg_restore is affected when used to generate a plain-format dump. Non-core use of \restrict would be affected, but we've not identified non-core use. Versions before PostgreSQL 18.5, 17.11, 16.15, 15.19, and 14.24 are affected.

Affected Version(s)

PostgreSQL 18 < 18.5

PostgreSQL 17 < 17.11

PostgreSQL 16 < 16.15

References

https://www.postgresql.org/support/security/CVE-2026-18408/

CVSS V3.1

Score:
8.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

The PostgreSQL project thanks Lucas Velgus, Filip Janus, and Daniel Bakker for reporting this problem.
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