What is CVE-2026-13763?

CVE-2026-13763 is a critical-severity vulnerability in Amazon Application Load Balancer, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2026-06-29.

How severe is CVE-2026-13763?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Amazon Application Load Balancer

CVE-2026-13763

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 )

Vulnerability class: HTTP Request Smuggling

EPSS: 0.005 (38.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Amazon Application_load_balancer
Aws Application Load Balancer — versions 0

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory, Vendor Advisory)
ff89ba41-3aa1-4d27-914a-91399e9639e5 (Product, mitigation)

Frequently asked questions

What is CVE-2026-13763?: CVE-2026-13763 is a critical-severity vulnerability in Amazon Application Load Balancer, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2026-06-29.
How severe is CVE-2026-13763?: Critical severity. CVSS v3 base score is 9.8 out of 10.