Vulnerability in Amazon Gateway API listener rule generation logic (CVE-2026-15738)
Summary
Vulnerability in Amazon Gateway API listener rule generation logic (CVE-2026-15738). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
Bulletin ID: 2026-055-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 07/14/2026 13:30 PM PDT Description: The AWS Load Balancer Controller is an open-source Kubernetes controller that manages AWS Elastic Load Balancing resources for Kubernetes clusters. We identified CVE-2026-15738, an incorrect rule precedence ordering issue in the Gateway API listener rule generation logic. When both an HTTPRoute and a GRPCRoute are attached to the same Application Load Balancer (ALB) HTTPS listener with the same hostname, the controller assigns ALB listener rule priorities based on route kind rather than route specificity. This causes all HTTPRoute-derived rules to receive lower ALB priority numbers, evaluated first by the ALB, than GRPCRoute-derived rules, regardless of which route is more specific. A namespace-scoped user with permission to create HTTPRoute objects in a namespace admitted by a shared Gateway can create a catch-all HTTPRoute that intercepts traffic intended for a more-specific GRPCRoute in another namespace. Impacted versions: AWS Load Balancer Controller v3.4.1 and any version that includes support for attaching both HTTPRoute and GRPCRoute to the same listener (introduced in PR #4794) Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.
Source: AWS Security Bulletins NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-15738 has been found in Amazon Gateway API listener rule generation logic.
Successful exploitation can lead to full system takeover. CVSS score: 8.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Amazon Gateway API listener rule generation logic CVE-2026-15738" on the vendor's site.
CVE-2026-15738 (Amazon Gateway API listener rule generation logic) — CWE-653 / CVSS v3 8.5
Attack vector: remote (network-reachable) / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-653) exists in Amazon Gateway API listener rule generation logic.
Check the vendor advisory for the affected versions of Amazon Gateway API listener rule generation logic.
Severity: High (CVSS 8.5/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Amazon Gateway API listener rule generation logic を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- AWS aws.amazon.com
- web aws.amazon.com
- web github.com