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CVE-2026-107348

Integer overflow causes an infinite loop in message buffer growth in PgBouncer

5.9 MediumFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.39%Unchanged since Oct 15, 2026
90%50%10%1%

What each source reports

CVE List Score used 5.9

Integer overflow causes an infinite loop in message buffer growth in PgBouncer

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.

Record
CVE-2026-107348
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-835
Updated
2026-11-02
EUVDEUVD-2026-101498 5.9

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.

Record
EUVD-2026-101498
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
GitHub AdvisoriesGHSA-982p-g5h4-w372 5.9

Integer overflow in the message buffer growth logic (mbuf_make_room) in PgBouncer 1.21.0 through...

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.

Record
GHSA-982p-g5h4-w372
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190
Updated
2026-11-02
NVD 5.9

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.

Record
CVE-2026-107348
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-835
Updated
2026-11-02
OSVDEBIAN-CVE-2026-107348 5.9

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.

Record
DEBIAN-CVE-2026-107348
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVRHSA-2026:83843 8.8

Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update

Record
RHSA-2026:83843
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-107348 5.9

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.

Record
UBUNTU-CVE-2026-107348
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVAZL-108195 No score

CVE-2026-107348 affecting package pgbouncer for versions less than 1.26.1-1

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.

Record
AZL-108195
Updated
2026-11-02
OSVBIT-pgbouncer-2026-107348 No score

Integer overflow causes an infinite loop in message buffer growth in PgBouncer

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.

Record
BIT-pgbouncer-2026-107348
Updated
2026-11-02

Affected packages

Affected packages
PackageAffectedFixed
pgbouncer
Azure Linux:3
before 1.26.1-1
1.26.1-1
pgbouncer
Bitnami
1.21.0 up to 1.26.1
1.26.1
pgbouncer
Debian:12
All versions, plus listed versions
1.18.0-11.18.0-1+deb12u11.19.0-11.19.1-11.20.0-1
Show 20 moreShow less
1.20.1-11.21.0-11.22.0-11.22.1-11.23.0-11.23.1-11.24.0-21.24.0-31.24.1-11.25.0-11.25.0-21.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-61.26.1-1
None known
pgbouncer
Debian:13
All versions, plus listed versions
1.24.1-11.24.1-1+deb13u11.24.1-1+deb13u21.25.0-11.25.0-2
Show 9 moreShow less
1.25.1-11.25.2-11.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-61.26.1-1
None known
pgbouncer
Debian:14
before 1.26.1-1, plus listed versions
1.24.1-11.25.0-11.25.0-21.25.1-11.25.2-1
Show 6 moreShow less
1.26.0-11.26.0-21.26.0-31.26.0-41.26.0-51.26.0-6
1.26.1-1
pgbouncer
Red Hat:hummingbird:1
From an advisory covering 3 CVEs
before 0:1.26.1-1.hum1
0:1.26.1-1.hum1
pgbouncer
Ubuntu:16.04:LTS
All versions, plus listed versions
1.5.5-11.6.1-11.7-1
None known
pgbouncer
Ubuntu:18.04:LTS
All versions, plus listed versions
1.7.2-3build11.7.2-65-g2b8e6cf-11.8.1-11.8.1-1build1
None known
pgbouncer
Ubuntu:20.04:LTS
All versions, plus listed versions
1.10.0-11.10.0-1build11.11.0-11.12.0-21.12.0-3
None known
pgbouncer
Ubuntu:22.04:LTS
All versions, plus listed versions
1.15.0-11.16.1-1ubuntu1
None known
pgbouncer
Ubuntu:24.04:LTS
All versions, plus listed versions
1.20.0-11.21.0-11.22.0-11.22.0-1build11.22.0-1build31.22.0-1build4
None known
pgbouncer
Ubuntu:26.10
All versions, plus listed versions
1.25.1-11.25.2-11.25.2-1ubuntu1
None known
pgbouncer
Ubuntu:26.04:LTS
All versions, plus listed versions
1.24.1-11.25.0-21.25.1-1
None known

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-107348 is a medium vulnerability (CVSS 5.9) in pgbouncer, published October 14, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.39%, the 33rd percentile. Fixed in pgbouncer 1.26.1-1.

References

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