Bug 2552741 (CVE-2026-107348)

Summary: CVE-2026-107348 pgbouncer: pgbouncer: Denial of Service via integer overflow in message buffer growth
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: medium    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in PgBouncer. An integer overflow in the message buffer growth logic allows a remote attacker to cause a Denial of Service (DoS) when a large maximum packet size is configured. By sending a specially crafted packet header declaring an excessively large length, an attacker can trigger an infinite loop in the buffer calculation. Because PgBouncer handles connections in a single process, this loop consumes a full CPU core and halts all pooled connections until the process is restarted.
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Bug Depends On: 2553064, 2553065    
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Description OSIDB Bzimport 2026-10-14 17:54:42 UTC 
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.