CVE-2026-107348
Integer overflow causes an infinite loop in message buffer growth in PgBouncer
CVSS Score
5.9
EPSS Score
0.0%
EPSS Percentile
0th
Integer overflow in the message buffer growth logic (mbuf_make_room) in PgBouncer 1.21.0 through 1.26.0 allows a remote attacker to cause a denial of service when max_packet_size is configured above 2147483648. A packet header declaring a length above 2^31 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 restarted. Since 1.23.0 the overflow is reachable before authentication with a five-byte packet header.
| CWE | CWE-190 CWE-835 |
| Vendor | n/a |
| Product | pgbouncer |
| Published | Oct 14, 2026 |
Stay Ahead of the Next One
Get instant alerts for n/a pgbouncer
Be the first to know when new medium vulnerabilities affecting n/a pgbouncer are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Affected Versions
n/a / PgBouncer
1.21.0 < 1.26.1
Credits
Thanks to Brian Cosgrove (@cosgroveb) for finding and reporting this issue.