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.

What this means for your business

It affects Postgresql. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.
FIRST's prediction model gives it a 0.5% chance of attack attempts being seen in the next 30 days, ranking above 38% of all known flaws.

What to do

1Check whether your company or your suppliers run Postgresql, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

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Scoring

CVSS: 8.8 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-242
Assigned by: f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Dates

Published: 2026-05-14
Last modified: 2026-08-25
Sources: NVD

Affected products

Postgresql Postgresql- 14.23, 15.0 - 15.18, 16.0 - 16.14, 17.0 - 17.10, 18.0 - 18.4

As listed in the NVD configuration data. Not a statement about your estate.