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CVE-2026-6664 PgBouncer CVE debrief

CVE-2026-6664 is a high-severity availability issue in PgBouncer before 1.25.2. According to the NVD entry and the vendor changelog reference, an integer overflow in network packet parsing can bypass a boundary check, and an unauthenticated remote attacker can crash PgBouncer by sending a malformed SCRAM authentication packet.

Vendor
PgBouncer
Product
PgBouncer
CVSS
HIGH 7.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-05-09
Original CVE updated
2026-07-24
Advisory published
2026-05-09
Advisory updated
2026-07-24

Who should care

Operators and administrators running PgBouncer in front of PostgreSQL services should prioritize this issue, especially if PgBouncer is reachable over the network and used for SCRAM authentication.

Technical summary

The reported weakness is CWE-190 (integer overflow). In affected PgBouncer versions before 1.25.2, malformed network input during SCRAM authentication can cause packet parsing to overflow an integer, bypass a boundary check, and terminate the process. The impact described in the source material is denial of service via crash; no confidentiality or integrity impact is indicated in the supplied data.

Defensive priority

High. The issue is network-reachable, requires no authentication, and can be triggered remotely to crash the service, creating an immediate availability risk.

Recommended defensive actions

  • Upgrade PgBouncer to version 1.25.2 or later.
  • Verify which hosts and services expose PgBouncer on the network and reduce exposure where possible.
  • Monitor PgBouncer instances for unexpected crashes or repeated authentication-related failures.
  • After upgrading, validate that the deployed build is the fixed release and that restart procedures are in place to restore service quickly.

Evidence notes

This debrief is based only on the supplied NVD record and the referenced PgBouncer changelog anchor. The source explicitly states that the issue affects PgBouncer before 1.25.2, that it involves an integer overflow in packet parsing, and that an unauthenticated remote attacker can crash the service using a malformed SCRAM authentication packet. CVSS vector supplied by NVD is AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-6664 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-6664

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-6664 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-6664

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://www.pgbouncer.org/changelog.html

    f86ef6dc-4d3a-42ad-8f28-e6d5547a5007

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.