SCRAM: Silent channel-binding authentication downgrade via unsupported certificate algorithms

Summary

CVECVE-2026-53712
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-17 19:17:16 UTC
Updated2026-07-17 20:17:25 UTC
DescriptionSCRAM (Salted Challenge Response Authentication Mechanism) is part of the family of Simple Authentication and Security Layer (SASL, RFC 4422) authentication mechanisms. Prior to 3.3, a flaw in com.ongres.scram:scram-client and com.ongres.scram:scram-common allows an attacker capable of a TLS man-in-the-middle attack to silently downgrade a connection from SCRAM-SHA-256-PLUS with channel binding to standard SCRAM-SHA-256 without channel binding when TlsServerEndpoint processes an X.509 certificate using a modern signature algorithm such as Ed25519; getChannelBindingData() can return an empty byte array after NoSuchAlgorithmException, and the ScramClient builder treats that as absent channel-binding data. This issue is fixed in version 3.3.

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from [email protected]

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-636 | CWE-757 | CWE-636 CWE-636: Not Failing Securely ('Failing Open') | CWE-757 CWE-757: Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.2HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/C...
4.0CNADECLARED8.2HIGHCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
High
Availability
None
Sub Conf.
None
Sub Integrity
Low
Sub Availability
None

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Ongres Scram affected < 3.3 Not specified

References

ReferenceSourceLinkTags
github.com/ongres/scram/releases/tag/3.3 [email protected] github.com
github.com/ongres/scram/security/advisories/GHSA-p9jg-fcr6-3mhf [email protected] github.com
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