Stack-based buffer overflow in PostgreSQL - CVE-2026-6477
Published: May 14, 2026
Vulnerability identifier: #VU131459
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber
CVE-ID: CVE-2026-6477
CWE-ID: CWE-121
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: PostgreSQL Global Development Group
Affected software:
PostgreSQL
PostgreSQL
Detailed vulnerability description
The vulnerability allows a remote attacker to overwrite client stack memory.
The vulnerability exists due to a stack-based buffer overflow in libpq lo_* functions when processing an arbitrarily large server response through PQfn(..., result_is_int=0, ...). A remote attacker can induce a victim client to process a crafted server response to overwrite client stack memory.
User interaction is required to invoke affected client functionality such as psql \lo_export or pg_dump. The issue affects lo_export(), lo_read(), lo_lseek64(), and lo_tell64().
How to mitigate CVE-2026-6477
Install security update from vendor's website.