CVE-2026-6668: Integer overflow causes an infinite loop in packet buffer growth in PgBouncer
Integer overflow in the packet buffer growth logic in PgBouncer through 1.25.2 allows an unauthenticated remote attacker to cause a denial of service. Sufficiently large input makes the buffer size computation overflow, leaving the growth loop unable to terminate. Because PgBouncer serves all clients from a single process, this saturates a CPU core and stalls every pooled connection until the process is killed. Both unauthenticated and authenticated code paths can reach the overflow.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
An unauthenticated remote attacker can trigger the denial of service. Authenticated code paths can also reach the overflow, so restricting client authentication does not eliminate exposure.
What is the operational impact if exploitation succeeds?
The non-terminating buffer-growth loop saturates a CPU core and stalls every pooled connection because PgBouncer serves clients from a single process. Service remains stalled until the PgBouncer process is killed.
Which deployments are affected?
PgBouncer through version 1.25.2 is affected. The issue is reachable through both unauthenticated and authenticated paths.