CVE-2026-6477 HIGH

CVE-2026-6477: PostgreSQL libpq lo_* functions let server superuser overwrite client stack memory

Vendor N/A
Product PostgreSQL
Weakness CWE-242
Published May 14, 2026
Last update June 30, 2026

CVSS base score

8.8/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction Required
Confidentiality High
Integrity High

CVSS vector

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

What the vulnerability does

01Description

Use of inherently dangerous function PQfn(..., result_is_int=0, ...) in PostgreSQL libpq lo_export(), lo_read(), lo_lseek64(), and lo_tell64() functions allows the server superuser to overwrite a client stack buffer with an arbitrarily-large response. Like gets(), PQfn(..., result_is_int=0, ...) stores arbitrary-length, server-determined data into a buffer of unspecified size. Because both the \lo_export command in psql and pg_dump call lo_read(), the server superuser can overwrite pg_dump or psql stack memory. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.

Key dates

02Disclosure timeline

May 14, 2026 CVE published
June 30, 2026 Record updated