---
id: "CVE-2026-103505"
kind: "vulnerability"
aliases: ["CVE-2026-103505"]
title: "AWS EFS CSI Driver: mount option injection via mounttargetipmap volume attribute"
severity: "medium"
cvss: 6.9
epss: 0.00432
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["aws", "eks", "infrastructure", "kubernetes", "lab-disclosure", "storage"]
not_affected_if: ["driver-below-v3.1.0-or-above-v3.4.2", "only-admins-create-storage-objects"]
published_at: "2026-10-01T16:17:36+00:00"
first_seen_at: "2026-10-24T18:43:45+00:00"
updated_at: "2026-10-25T12:38:49+00:00"
sources: [{"source": "lab", "url": "https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/", "first_seen_at": "2026-10-24T18:43:45+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-103505", "first_seen_at": "2026-10-24T18:53:56+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-103505", "first_seen_at": "2026-10-25T12:38:49+00:00"}]
---

# AWS EFS CSI Driver: mount option injection via mounttargetipmap volume attribute

The Amazon EFS CSI Driver lets a user who can create PersistentVolumes inject extra mount options through the mounttargetipmap volumeAttribute, because comma-separated values are parsed as separate options. The attacker can change how an EFS volume is mounted on the Kubernetes node.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed driver version in the cluster, for example `kubectl get pods -n kube-system` and read the image tag of the efs-csi-controller and efs-csi-node pods.
- Check who can create PersistentVolumes and StorageClasses with `kubectl auth can-i create persistentvolumes --all-namespaces` and review the RBAC bindings.

## Fix

- Upgrade the Amazon EFS CSI Driver to `v3.5.0`.
- Restrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC.
- Patch any forked or derivative copies of the driver code.

## Timeline

- 2026-10-24T18:43:45+00:00 lab https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/ — AWS: CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver
- 2026-10-24T18:53:56+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-103505
- 2026-10-25T12:38:49+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-103505

## Documents

- [advisory] AWS: CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/

## From the sources

CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver

### CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver

Bulletin ID: 2026-120-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/01/2026 08:30 AM PDT

Description:

The Amazon EFS CSI Driver is a Container Storage Interface driver that allows Kubernetes clusters to use Amazon Elastic File System. We identified CVE-2026-103505, where an actor with PersistentVolume creation privileges can inject additional mount options through the mounttargetipmap volumeAttribute. Appending comma-separated values to a value inside that JSON map causes the mount utility to parse them as separate mount options.

Impacted versions: >= v3.1.0 AND <= v3.4.2

Resolution:

This issue has been addressed in Amazon EFS CSI Driver version v3.5.0. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds:

Restrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC, preventing untrusted users from supplying arbitrary field values.

References:

- CVE-2026-103505
- GHSA-pv26-6q9q-5773

 Please email aws-security@amazon.com with any security questions or concerns..

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