CVE-2026-6478

PostgreSQL discloses MD5-hashed passwords via covert timing channel

Published: 5/14/2026 Last updated: 5/14/2026 Reserved: 4/17/2026

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.

CNA assigner: PostgreSQL (f86ef6dc-4d3a-42ad-8f28-e6d5547a5007) Requested by: n/a

Metrics

Version	Score	Severity	Vector String
3.1	6.5	Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Opam packages affected (5)

conf-mingw-w64-postgresql-i686 conf-mingw-w64-postgresql-x86_64 conf-postgresql ocsigen-start postgresql

Products affected (1)

Product	Vendor	Version
PostgreSQL	n/a	32-bit Systems Service Pack 2 (Server Core installation)

References (1)

https://www.postgresql.org/support/security/CVE-2026-6478/

Credits (1)

The PostgreSQL project thanks Joe Conway for reporting this problem.