Algorithm Downgrade in Postgresql JDBC Driver - CVE-2026-54291
Published: June 30, 2026
Vulnerability identifier: #VU135919
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-54291
CWE-ID: CWE-757
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass channel-binding protection and enable a man-in-the-middle downgrade of authentication.
The vulnerability exists due to failing open and algorithm downgrade in ScramAuthenticator when processing certificates whose signature algorithm has no tls-server-end-point channel-binding hash. A remote attacker can present a certificate with an unsupported signature algorithm while intercepting the TLS connection to bypass channel-binding protection and enable a man-in-the-middle downgrade of authentication.
Only connections configured with channelBinding=require are affected.
Affected software
Postgresql JDBC Driver
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data
Maximo Application Suite - IoT Component
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data
Maximo Application Suite - IoT Component
How to mitigate CVE-2026-54291
Install security update from vendor's website.
Postgresql JDBC Driver - update to 42.7.12
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data - update to 5.4.0 Patch 3
Maximo Application Suite - IoT Component - addressed in versions 9.0.22, 9.1.13, 9.2.1
IBM Watson Speech Services Cartridge for IBM Cloud Pak for Data - update to 5.4.0 Patch 3
Maximo Application Suite - IoT Component - addressed in versions 9.0.22, 9.1.13, 9.2.1