CVE-2026-53712Network attack vector

Authentication downgrade via swallowed certificate algorithm error

Published Jul 17, 2026 · Updated Jul 17, 2026

Authentication downgrade in OnGres SCRAM before 3.3 allows man-in-the-middle attackers to bypass required channel binding over TLS. TlsServerEndpoint swallows a NoSuchAlgorithmException for certificate algorithms such as Ed25519 and returns empty channel-binding data, which the client builder treats as unavailable rather than failed. Exploitation requires TLS interception, strict channel-binding enforcement, and a server certificate whose signature name cannot be parsed; the result is silent fallback from SCRAM-SHA-256-PLUS to SCRAM-SHA-256.

CVSS severity8.2
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication downgrade in OnGres SCRAM before 3.3 allows man-in-the-middle attackers to bypass required channel binding over TLS. TlsServerEndpoint swallows a NoSuchAlgorithmException for certificate algorithms such as Ed25519 and returns empty channel-binding data, which the client builder treats as unavailable rather than failed. Exploitation requires TLS interception, strict channel-binding enforcement, and a server certificate whose signature name cannot be parsed; the result is silent fallback from SCRAM-SHA-256-PLUS to SCRAM-SHA-256.

The record

CVE
CVE-2026-53712
Published
Jul 17, 2026
Updated
Jul 17, 2026
Vendor
OnGres
Product
SCRAM
Classifications
CWE-757, CWE-636, T1557
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 17, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 3.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OnGres · SCRAMversion=< 3.3

Published CVSS scores

8.2GitHub Advisory DatabaseCVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N
5.9Amazon LinuxCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-757Selection of Less-Secure Algorithm During Negotiation ('Algorithm Downgrade')
CWE-636Not Failing Securely ('Failing Open')
T1557Adversary-in-the-Middle

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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