CVE-2026-13763

High

Published: 29 June 2026

Published

29 June 2026

Modified

01 July 2026

KEV Added

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Patch

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CVSS Score v4 7.9 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Score 0.0047 37.5th percentile

Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-13763 is a high-severity HTTP Request/Response Smuggling (CWE-444) vulnerability in Amazon Application Load Balancer. Its CVSS base score is 7.9 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 37.5th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

🇪🇺 ENISA EUVD: EUVD-2026-40221

Vulnerability details

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 )

CWE(s): CWE-444

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1190 Exploit Public-Facing Application Initial Access

Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.

attack.mitre.org →

T1211 Exploitation for Stealth Stealth

Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.

attack.mitre.org →

Why these techniques?

Vuln enables remote bypass of WAF body inspection on public-facing ALB via HTTP/2 frame fragmentation (CWE-444), directly facilitating stealthy exploitation of the exposed application.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0