CVE-2026-6478 — PostgreSQL discloses MD5-hashed passwords via covert timing channel

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
n/a / PostgreSQL	affected 18 before 18.4; affected 17 before 17.10; affected 16 before 16.14; affected 15 before 15.18; affected 0 before 14.23

CWE

CWE-385

References

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

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in PostgreSQL. This vulnerability, a covert timing channel, exists in the comparison of MD5-hashed passwords during authentication. A remote attacker could exploit this to recover user credentials, gaining unauthorized access to the database. This issue specifically impacts databases that retain MD5-hashed passwords from upgrades of PostgreSQL 13 or earlier.