CVE-2026-6669Network attack vectorHinoki check available

Service interruption via unbounded SCRAM iteration count

Published Sep 23, 2026 · Updated Sep 23, 2026

Denial of service in PgBouncer 1.25.2 and earlier allows malicious PostgreSQL backends to halt pooled traffic during SCRAM login. Its SCRAM client accepts a backend-supplied iteration count without an upper bound and performs the requested key-derivation work synchronously. Control of a configured backend is required; one crafted authentication exchange can monopolize the single process and stop service for every pooled database and client.

CVSS severityUnavailable
Unscored
EPSS probability0.31%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Denial of service in PgBouncer 1.25.2 and earlier allows malicious PostgreSQL backends to halt pooled traffic during SCRAM login. Its SCRAM client accepts a backend-supplied iteration count without an upper bound and performs the requested key-derivation work synchronously. Control of a configured backend is required; one crafted authentication exchange can monopolize the single process and stop service for every pooled database and client.

The record

CVE
CVE-2026-6669
Published
Sep 23, 2026
Updated
Sep 23, 2026
Vendor
PgBouncer
Product
PgBouncer
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 23, 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=0 <=1.25.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

PgBouncer · PgBouncerversion=0 <=1.25.2

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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