Description
Improper authentication in PgBouncer 1.17.0 through 1.26.0 allows a remote attacker who knows the password of a user listed in auth_file to log in as any other user that authenticates using SCRAM, including PgBouncer admin users and backend superusers. A second StartupMessage sent during SCRAM authentication against a non-existent database is not rejected and switches the user being logged in as, while the SCRAM exchange is still verified against the keys of the first user.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | PgBouncer | 1.17.0 – < 1.26.1 | 1.26.1 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pgbouncer | 1.26.1-1 | — |
| Debian 13 | pgbouncer | No fix yet | — |
| Debian 12 | pgbouncer | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pgbouncer | No fix yet | — |
| Ubuntu 26.04 LTS | pgbouncer | No fix yet | — |
| Ubuntu 24.04 LTS | pgbouncer | No fix yet | — |
| Ubuntu 22.04 LTS | pgbouncer | No fix yet | — |
| Ubuntu 20.04 LTS | pgbouncer | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | pgbouncer | No fix yet | — |
| Ubuntu 16.04 LTS | pgbouncer | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | pgbouncer | 1.26.1-1.hum1 | RHSA-2026:83843 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | pgbouncer | 1.26.1-1 | — |
Advisories 2
- WID-SEC-2026-3906 PgBouncer: Mehrere Schwachstellen BSI CERT-Bund (WID) · Oct 18, 2026
- RHSA-2026:83843 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 18, 2026