PgBouncer up to 1.26.0 Message Buffer Growth Logic mbuf_make_room max_packet_size integer overflow

Summaryinfo

A vulnerability, which was classified as problematic, has been found in PgBouncer up to 1.26.0. Affected by this issue is the function mbuf_make_room of the component Message Buffer Growth Logic. Performing a manipulation of the argument max_packet_size results in integer overflow. This vulnerability is reported as CVE-2026-107348. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability, which was classified as problematic, was found in PgBouncer up to 1.26.0. This affects the function mbuf_make_room of the component Message Buffer Growth Logic. The manipulation of the argument max_packet_size with an unknown input leads to a integer overflow vulnerability. CWE is classifying the issue as CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. This is going to have an impact on availability. The summary by CVE is:

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.

It is possible to read the advisory at pgbouncer.org. This vulnerability is uniquely identified as CVE-2026-107348 since 10/07/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.26.1 eliminates this vulnerability.

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Productinfo

Name

• PgBouncer

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26.0

CPE 2.3info

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CPE 2.2info

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