by Kastro
Paper/Archive/CVE-2026-13763

CVE-2026-13763

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

EPSS 0.7%CVSS 9.8
critical.is priorityof 100
40
CVSS 9.8 (CNA)9.8 / 10 × 3029.4Not in CISA KEV+300.0EPSS percentile 52.3.523 × 2010.5No public exploit+100.0SSVC exploitation: none+100.0
Description · from the CVE record

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

ProductAffectedFixed inSource
AWS Application Load Balancerall versions–CNA

Scores by source

AMZN (CNA)9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
AMZN (CNA)7.9CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

refdocs.aws.amazon.com/elasticloadbalancing/latest/application/edit-target-group-attributes.html#waf-http2-inspectionadvisoryaws.amazon.com/security/security-bulletins/2026-048-aws