AWS Application Load Balancer Configuration request smuggling

Summaryinfo

A vulnerability, which was classified as critical, was found in AWS Application Load Balancer. Impacted is an unknown function of the component Configuration Handler. Executing a manipulation can lead to request smuggling. This vulnerability appears as CVE-2026-13763. The attack may be performed from remote. There is no available exploit. This product is a managed service, which means users themselves cannot handle vulnerability countermeasures.

Detailsinfo

A vulnerability classified as critical was found in AWS Application Load Balancer (affected version not known). This vulnerability affects some unknown functionality of the component Configuration Handler. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

Inconsistent interpretation of HTTP/2 requests in AWS Application Load Balancer with AWS WAF enabled might allow remote actors to bypass AWS WAF managed rule body inspection via crafted HTTP/2 requests that fragment the request body across frames so that only a partial body is inspected. This issue only impacts HTTP/2 ALB target groups. To remediate this issue, customers should enable the "Inspect after sufficient data" target group configuration associated to an ALB load balancer. Refer to: ( https://docs.aws.amazon.com/elasticloadbalancing/latest/application/edit-target-group-attributes.html#waf-http2-inspection )

The advisory is available at docs.aws.amazon.com. This vulnerability was named CVE-2026-13763 since 06/29/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. The technical details are unknown and an exploit is not available. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/30/2026).

This product is available as a managed service. Users are not able to maintain vulnerability countermeasures themselves.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• AWS

Name

• Application Load Balancer

Managed Service

• yes

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• 🔒

CPE 2.2info

• 🔒

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If you want to get best quality of vulnerability data, you may have to visit VulDB.

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