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Critical · 9.8 CVE-2026-13763 EUVD-2026-40221GHSA-9m3p-hghr-5v6c

HTTP/2 Stream Parser Confusion Body-Inspection Bypass in AWS Application Load Balancer with AWS WAF

Published Jun 29, 2026 · Updated Jun 29, 2026 · Assigned by AMZN

Description

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 )

Affected products

VendorProductAffectedFixed
AWS AWS Application Load Balancer — —

References