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High

PostgreSQL JDBC Driver: Silent channel-binding authentication downgrade via unsupported certificate algorithms

  • Disclosed: 21.07.2026
  • Updated: 11.10.2026 13:20

Impact

channelBinding=require connections can be silently downgraded from SCRAM-SHA-256-PLUS (with channel binding) to plain SCRAM-SHA-256 (without it), losing the man-in-the-middle protection the setting is meant to guarantee. An attacker who can intercept the TLS connection triggers the downgrade with a certificate whose signature algorithm has no tls-server-end-point channel-binding hash. Examples are Ed25519, Ed448, and post-quantum algorithms.

Two issues combine in releases 42.7.4 through 42.7.11:

  1. The bundled com.ongres.scram:scram-client (3.1 or 3.2) returns an empty byte array instead of failing when it cannot derive the binding hash for such a certificate. This is the library issue tracked as GHSA-p9jg-fcr6-3mhf.
  2. pgJDBC does not enforce channelBinding=require where it matters. ScramAuthenticator checks only that the server advertised a -PLUS mechanism; it neither rejects the empty binding nor checks that the negotiated mechanism uses channel binding. The connection therefore downgrades silently, and would do so even against a fixed scram-client, because the missing enforcement is in pgJDBC's own code.

Only connections that set channelBinding=require are affected. Under the default prefer policy, and under allow or disable, falling back to plain SCRAM is the documented behaviour. Releases before 42.7.4 are unaffected, because they do not support channel binding.

Patches

Fixed in pgJDBC 42.7.12. pgJDBC now enforces channel binding in its own code, independently of the scram-client version:

  • Under channelBinding=require, it fails the connection when no channel-binding data can be extracted from the server certificate, instead of passing an empty value to the SCRAM client. The error names the certificate signature algorithm.
  • After negotiation, it requires the selected mechanism to use channel binding (a -PLUS mechanism) whenever channelBinding=require is set, regardless of how negotiation resolved.

Upgrade to 42.7.12 or later.

Workarounds

No pgJDBC setting restores channel-binding enforcement on an affected release; upgrading is the fix.

If you cannot upgrade immediately, verify the server certificate at the TLS layer so that a man-in-the-middle cannot present a substitute certificate. Set sslmode=verify-full with a truststore that contains only your server's CA. This defence is independent of channel binding and blocks the same attacker. Connections that rely on channelBinding=require in place of certificate verification have no equivalent workaround and should upgrade.

References

Affected software

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.postgresql:postgresql >= 42.7.4, < 42.7.12 42.7.12

References

CVSS score -
CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N
Weakness (CWE)
CWE-636, CWE-757
Platform
Java / Kotlin (Maven)
Package
org.postgresql:postgresql
Disclosed
21.07.2026
Updated
11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-j92g-9f8w-j867 - CC BY 4.0

Vulnerability history: org.postgresql:postgresql

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (10) in the archive
Total entries
10
First → latest
02.2022 07.2026
Without a fix
0
Exploited in attacks
0

Severity breakdown

  • Critical 1
  • High 7
  • Medium 2

Disclosures per year

Severity:
  1. PostgreSQL JDBC Driver: Silent channel-binding authentication downgrade via unsupported certificate algorithms this entry
    High CVE-2026-54291 >= 42.7.4, < 42.7.12 42.7.12
  2. pgjdbc: Unbounded PBKDF2 iterations in SCRAM authentication allows CPU exhaustion DoS
    High · 7.5 CVE-2026-42198 >= 42.2.0, < 42.7.11 42.7.11
  3. pgjdbc Client Allows Fallback to Insecure Authentication Despite channelBinding=require Configuration
    High · 8.2 CVE-2025-49146 >= 42.7.4, < 42.7.7 42.7.7
  4. org.postgresql:postgresql vulnerable to SQL Injection via line comment generation
    Critical · 10.0 CVE-2024-1597 < 42.2.28, >= 42.3.0, < 42.3.9, >= 42.4.0, < 42.4.4, >= 42.5.0, < 42.5.5, >= 42.6.0, < 42.6.1, >= 42.7.0, < 42.7.2 42.2.28, 42.3.9, 42.4.4, 42.5.5, 42.6.1, 42.7.2
  5. PostgreSQL JDBC Driver SQL Injection in ResultSet.refreshRow() with malicious column names
    High · 7.1 CVE-2022-31197 < 42.2.26, >= 42.4.0, < 42.4.1, >= 42.3.0, < 42.3.7 42.2.26, 42.4.1, 42.3.7
  6. Unescaped parameters in the PostgreSQL JDBC driver
    High CVE-2012-1618 < 8.2 8.2
  7. Improper Restriction of XML External Entity Reference
    High · 7.7 CVE-2020-13692 >= 9.4.1212.jre6, < 42.2.13 42.2.13
  8. pgjdbc Does Not Check Class Instantiation when providing Plugin Classes
    High · 7.0 CVE-2022-21724 >= 9.4.1208, < 42.2.25, >= 42.3.0, < 42.3.2 42.2.25, 42.3.2

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