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Vulnerability record · CVE-2021-3935 · published 22 November 2021

CVE-2021-3935: Pgbouncer sql injection vulnerability

Pgbouncer · Pgbouncer

When PgBouncer is configured to use "cert" authentication, a man-in-the-middle attacker can inject arbitrary SQL queries when a connection is first established, despite the use of TLS certificate verification and encryption. This flaw affects PgBouncer versions prior to 1.16.1.

8.1 CVSS 3.1 High EPSS 1.1% · top 35.3% CWE-89 · SQL injectionCWE-295 · Improper certificate validation
8.1CVSS 3.1 base score, v2 5.1
1.1%EPSS exploitation probability, 30 days
NoNot in CISA KEV
4Affected product versions listed by NVD
9References
17 Jun 2026Last modified by NVD

Description

When PgBouncer is configured to use "cert" authentication, a man-in-the-middle attacker can inject arbitrary SQL queries when a connection is first established, despite the use of TLS certificate verification and encryption. This flaw affects PgBouncer versions prior to 1.16.1.

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.pgbouncer.org/changelog.html#pgbouncer-116x Release NotesVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2021251 Issue TrackingThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/02/msg00016.html Mailing ListThird Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNPCV3KRDI5PLLLKADFVIOH
http://www.pgbouncer.org/changelog.html#pgbouncer-116x Release NotesVendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2021251 Issue TrackingThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/02/msg00016.html Mailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2025/05/msg00032.html
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TNPCV3KRDI5PLLLKADFVIOH

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Source: NIST National Vulnerability Database (record CVE-2021-3935), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.