aws-load-balancer-controller: Improper Isolation or Compartmentalization
CVE-2026-15738 is a high-severity improper isolation or compartmentalization vulnerability in aws-load-balancer-controller from Amazon, with a CVSS 3.1 base score of 8.5 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 3.4.2 as the first without the flaw, so updating aws-load-balancer-controller to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.65% chance of exploitation within 30 days, higher than 52% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update aws-load-balancer-controller to 3.4.2 or a later version.
- Read the advisory on aws.amazon.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Amazon | aws-load-balancer-controller | before 3.4.2 | 3.4.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 5.8 | Medium | CNA |
| CVSS 3.1 | 8.5 | High | CNA |
Official description
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.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Isolation or Compartmentalization
The product does not properly compartmentalize or isolate functionality, processes, or resources that require different privilege levels, rights, or permissions.
How developers prevent this class of flaw
- Break up privileges between different modules, objects, or entities. Minimize the interfaces between modules and require strong access control between them.
More Improper Isolation or Compartmentalization vulnerabilities (CWE-653)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Improper Isolation or Compartmentalization vulnerabilities
- 7.2 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.4 High severity
- 8.1 High severity
- 10.0 Critical severity
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