Vulnerability Report

CVE-2026-6477

Title: Buffer overflow in libpq functions via server superuser

Memory Corruption

Proof Of Concept

No public PoC currently indexed for CVE-2026-6477.

CWE Category CWE-242

Published Date May 14, 2026

Modified Date Jul 24, 2026

Exploit Status Not Found

Score 8.8 CVSS v3.1

Exploit Probability (EPSS)

0.45%

Vulnerability Summary

CVE-2026-6477: 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.

Impacted Vendors

postgresql 1

anynines 1

Reference Links

https://www.postgresql.org/support/security/CVE-2026-6477/

CVSS v3.1

Source Entity f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Severity HIGH

8.8

Attack Vector

NETWORK

Complexity

LOW

Privileges

N/A

Interaction

REQUIRED

Confidentiality

N/A

Integrity

N/A

Availability

N/A

Scope

UNCHANGED

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