AWS LBC <3.4.2: Auth Remoteuser Can Spoof gRPC via HTTPRoute
CVE-2026-15738 Published on July 14, 2026
Cross-namespace traffic interception via incorrect route precedence ordering in AWS Load Balancer Controller
Incorrect behavior order in the Gateway API listener-rule generation in Amazon AWS Load Balancer Controller before 3.4.2 might allow an authenticated remote user to intercept, spoof, or deny another namespace's gRPC traffic on a shared Gateway via a crafted HTTPRoute resource.
To mitigate this issue, users should upgrade to version 3.4.2.
Vulnerability Analysis
CVE-2026-15738 is exploitable with network access, and requires small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.
Weakness Type
What is a Separation of Privilege Vulnerability?
The product does not sufficiently compartmentalize functionality or processes that require different privilege levels, rights, or permissions. When a weakness occurs in functionality that is accessible by lower-privileged users, then without strong boundaries, an attack might extend the scope of the damage to higher-privileged users.
CVE-2026-15738 has been classified to as a Separation of Privilege vulnerability or weakness.
Products Associated with CVE-2026-15738
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Affected Versions
Amazon aws-load-balancer-controller:- Before 3.4.2 is affected.