HTTP/2 Stream Parser Confusion Body-Inspection Bypass in AWS Application Load Balancer with AWS WAF
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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 )
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-13763
- 2026-10-03 Alias added: GHSA-9m3p-hghr-5v6c
References
Sources
- CVE-2026-13763 · CVE Program
- CVE-2026-13763 · NVD
- FIRST EPSS
- GHSA-9m3p-hghr-5v6c · GitHub Advisory Database · CC BY 4.0
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