CVE-2026-6478

Description

Covert timing channel in comparison of MD5-hashed password in PostgreSQL authentication allows an attacker to recover user credentials sufficient to authenticate. This does not affect scram-sha-256 passwords, the default in all supported releases. However, current databases may have MD5-hashed passwords originating in upgrades from PostgreSQL 13 or earlier. Versions before PostgreSQL 18.4, 17.10, 16.14, 15.18, and 14.23 are affected.

How to fix CVE-2026-6478

To remediate CVE-2026-6478, upgrade the affected package to a fixed version below.

—upgrade to 15.18-r0 or later
—upgrade to 16.14-r0 or later
—upgrade to 17.10-r0 or later
—upgrade to 18.4-r0 or later
—upgrade to 14.23.0 or later
—no fix listed
—upgrade to 15.18-0+deb12u1 or later
—upgrade to 17.10-0+deb13u1 or later
—upgrade to 18.4-1 or later

Is CVE-2026-6478 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (9)

from 0, < 15.18-r0
from 0, < 16.14-r0
from 0, < 17.10-r0
from 0, < 18.4-r0
from 0, < 14.23.0, >= 15.0.0, < 15.18.0, >= 16.0.0, < 16.14.0, >= 17.0.0, < 17.10.0, >= 18.0.0, < 18.4.0
from 0
from 0, < 15.18-0+deb12u1
from 0, < 17.10-0+deb13u1
from 0, < 18.4-1

CVSS scores

Source	Version	Severity	Vector
osv	CVSS 3.1	MEDIUM6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N