How severe is CVE-2026-6665?

CVE-2026-6665 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-6665 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-6665?

CVE-2026-6665 affects Pgbouncer. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-6665?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-6665 have an EU (EUVD) identifier?

Yes. CVE-2026-6665 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28877.

When was CVE-2026-6665 published?

CVE-2026-6665 was published on 2026-05-09 and last updated on 2026-06-17.

CVE-2026-6665

CVE-2026-6665 is a high-severity vulnerability in Pgbouncer with a CVSS 3.x base score of 8.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-121.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (29th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-28877
Weakness: CWE-121
Affected product: Pgbouncer
Published: 2026-05-09
Last modified: 2026-06-17

Description

The SCRAM code in PgBouncer before 1.25.2 did not check the return value of strlcat() correctly when building the contents of the SCRAM client-final-message. A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.

Frequently asked questions

What is CVE-2026-6665?: The SCRAM code in PgBouncer before 1.25.2 did not check the return value of strlcat() correctly when building the contents of the SCRAM client-final-message. A malicious backend that sends a SCRAM server-final-message with a long nonce can trigger a stack overflow.
How severe is CVE-2026-6665?: CVE-2026-6665 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-6665 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (29th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-6665?: CVE-2026-6665 affects Pgbouncer. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-6665?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-6665 have an EU (EUVD) identifier?: Yes. CVE-2026-6665 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-28877.
When was CVE-2026-6665 published?: CVE-2026-6665 was published on 2026-05-09 and last updated on 2026-06-17.

References

https://www.pgbouncer.org/changelog.html#pgbouncer-125x

Affected products (1)

cpe:2.3:a:pgbouncer:pgbouncer:*:*:*:*:*:*:*:*

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