CVE-2026-6664
Description
A flaw was found in PgBouncer. An integer overflow in the network packet parsing code allows an unauthenticated remote attacker to bypass a boundary check by sending a malformed SCRAM authentication packet. This can lead to a crash, resulting in a Denial of Service (DoS) for the PgBouncer instance.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
To mitigate this issue, restrict network access to the PgBouncer instance to only trusted clients and networks. This can be achieved by configuring firewall rules to limit inbound connections to the PgBouncer port. For example, using `firewalld` to allow access only from specific sources:
bash
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="<TRUSTED_IP_ADDRESS>" port port="6432" protocol="tcp" accept'
firewall-cmd --reload
Replace `<TRUSTED_IP_ADDRESS>` with the IP address or network range of your trusted clients. Restricting access to `localhost` only can be done with:
bash
firewall-cmd --permanent --add-rich-rule='rule family="ipv4" source address="127.0.0.1" port port="6432" protocol="tcp" accept'
firewall-cmd --reload
This may impact legitimate client connections if not configured to include all necessary trusted sources. A restart of the firewall service is required for changes to take effect.
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart; DoS: Resource Consumption (Memory); DoS: Instability
This weakness can generally lead to undefined behavior and therefore crashes. When the calculated result is used for resource allocation, this weakness can cause too many (or too few) resources to be allocated, possibly enabling crashes if the product requests more resources than can be provided.
Integrity
Technical Impact: Modify Memory
If the value in question is important to data (as opposed to flow), simple data corruption has occurred. Also, if the overflow/wraparound results in other conditions such as buffer overflows, further memory corruption may occur.
Confidentiality,Availability,Access Control
Technical Impact: Execute Unauthorized Code or Commands; Bypass Protection Mechanism
This weakness can sometimes trigger buffer overflows, which can be used to execute arbitrary code. This is usually outside the scope of the product's implicit security policy.
Availability,Other
Technical Impact: Alter Execution Logic; DoS: Crash, Exit, or Restart; DoS: Resource Consumption (CPU)
If the overflow/wraparound occurs in a loop index variable, this could cause the loop to terminate at the wrong time - too early, too late, or not at all (i.e., infinite loops). With too many iterations, some loops could consume too many resources such as memory, file handles, etc., possibly leading to a crash or other DoS.
Access Control
Technical Impact: Bypass Protection Mechanism
If integer values are used in security-critical decisions, such as calculating quotas or allocation limits, integer overflows can be used to cause an incorrect security decision.
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