{"id":"GHSA-pv26-6q9q-5773","kind":"vulnerability","aliases":["GHSA-pv26-6q9q-5773"],"related":[],"title":"CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver","description":"CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver\n\n### CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver\n\nBulletin ID: 2026-120-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/01/2026 08:30 AM PDT\n\nDescription:\n\nThe 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.\n\nImpacted versions: >= v3.1.0 AND <= v3.4.2\n\nResolution:\n\nThis 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.\n\nWorkarounds:\n\nRestrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC, preventing untrusted users from supplying arbitrary field values.\n\nReferences:\n\n- CVE-2026-103505\n- GHSA-pv26-6q9q-5773\n\n Please email aws-security@amazon.com with any security questions or concerns..","summary":"The Amazon EFS CSI Driver lets a user with PersistentVolume creation rights inject extra mount options through the mounttargetipmap volumeAttribute, because comma-separated values appended inside that JSON map are parsed as separate mount options. An attacker can therefore pass arbitrary mount options to the mount utility on the node.","severity":"medium","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["aws","eks","infrastructure","kubernetes","lab-disclosure","storage"],"not_affected_if":["admin-only-pv-creation","patched-driver"],"how_to_check":"- Check the installed driver version (`aws-efs-csi-driver` image tag or Helm chart `appVersion`); affected versions are `v3.1.0` through `v3.4.2`.\n- List PersistentVolumes and StorageClasses that set `mounttargetipmap` and confirm only cluster administrators can create them.","fix":"- Upgrade the Amazon EFS CSI Driver to `v3.5.0` or later.\n- Restrict PersistentVolume and StorageClass creation to cluster administrators with Kubernetes RBAC.\n- Patch any forked or derivative copies of the driver code.","status":"open","published_at":null,"first_seen_at":"2026-10-24T18:43:45+00:00","triaged_at":"2026-10-25T04:51:41+00:00","updated_at":"2026-10-25T04:51:41+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-25T04:51:41Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade the Amazon EFS CSI Driver to `v3.5.0` or later.\n- Restrict PersistentVolume and StorageClass creation to cluster administrators with Kubernetes RBAC.\n- Patch any forked or derivative copies of the driver code.","reach":"internet","title":"Amazon EFS CSI Driver: mount option injection via PersistentVolume attribute","impact":"medium","summary":"The Amazon EFS CSI Driver lets a user with PersistentVolume creation rights inject extra mount options through the mounttargetipmap volumeAttribute, because comma-separated values appended inside that JSON map are parsed as separate mount options. An attacker can therefore pass arbitrary mount options to the mount utility on the node.","category":"infrastructure","nicknames":[],"who_cares":["kubernetes","aws","eks","storage"],"confidence":0.6,"needs_auth":"yes","worst_case":"Attacker injects arbitrary mount options into node-level mount commands","analyst_note":"","how_to_check":"- Check the installed driver version (`aws-efs-csi-driver` image tag or Helm chart `appVersion`); affected versions are `v3.1.0` through `v3.4.2`.\n- List PersistentVolumes and StorageClasses that set `mounttargetipmap` and confirm only cluster administrators can create them.","needs_analyst":false,"not_affected_if":["patched-driver","admin-only-pv-creation"],"who_is_affected":"Kubernetes clusters running the Amazon EFS CSI Driver between `v3.1.0` and `v3.4.2` are exposed, and the risk is greatest where tenants or untrusted users can create PersistentVolumes or StorageClasses. Clusters on a patched driver, or where only administrators control volume creation, are less exposed. The sources do not say whether non-EFS deployments are affected.","user_interaction":"no","needs_special_setup":"no","severity_if_unknown":"medium"},"cost_usd":0.000722,"input_tokens":3776,"output_tokens":689,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'-103505':3A,83C,94C,148C,250C '-120':106C '-2026':2A,82C,93C,147C,249C '..':265C '08':118C '10/01/2026':117C '2026':105C '30':119C '5773':16A,21A,255C '6q9q':15A,20A,254C 'actor':151C 'addit':158C 'address':198C 'administr':235C 'allow':135C 'amazon':8A,31B,88C,99C,124C,140C,200C 'append':55B,165C 'arbitrari':71B,244C 'attack':67B 'attent':114C 'aw':22B,107C,109C 'aws-security@amazon.com':258C 'bulletin':103C 'caus':177C 'cluster':137C,234C 'code':219C 'comma':52B,167C 'comma-separ':51B,166C 'concern':264C 'contain':130C 'content':110C 'creation':40B,154C,232C 'csi':10A,33B,90C,101C,126C,202C 'cve':1A,81C,92C,146C,248C 'date':116C 'deriv':218C 'descript':122C 'disclosur':28B 'driver':11A,34B,91C,102C,127C,133C,203C 'ef':9A,32B,89C,100C,125C,201C 'ek':23B 'elast':141C 'email':257C 'ensur':214C 'extra':43B 'field':245C 'file':142C 'fix':226C 'fork':216C 'ghsa':13A,18A,252C 'ghsa-pv26-6q9q':12A,17A,251C 'id':104C 'identifi':145C 'impact':188C 'import':112C 'incorpor':223C 'infrastructur':24B 'inject':6A,42B,86C,97C,157C 'insid':56B,173C 'interfac':132C 'issu':195C 'json':58B,175C 'kubernet':25B,136C,237C 'lab':27B 'lab-disclosur':26B 'latest':211C 'let':35B 'map':59B,176C 'mount':4A,44B,64B,72B,76B,84C,95C,159C,179C,186C 'mounttargetipmap':48B,163C 'new':225C 'node':80B 'option':5A,45B,65B,73B,85C,96C,160C,187C 'pars':61B,182C 'pass':70B 'patch':221C 'pdt':121C 'persistentvolum':39B,153C,229C 'pleas':256C 'prevent':239C 'privileg':155C 'public':115C 'pv26':14A,19A,253C 'question':262C 'rbac':238C 'recommend':207C 'refer':247C 'requir':113C 'resolut':193C 'restrict':228C 'right':41B 'scope':108C 'secur':261C 'separ':53B,63B,168C,185C 'storag':29B,131C 'storageclass':231C 'suppli':243C 'system':143C 'therefor':69B 'type':111C 'untrust':240C 'upgrad':208C 'use':139C,236C 'user':37B,241C 'util':77B,180C 'v3.1.0':190C 'v3.4.2':192C 'v3.5.0':205C 'valu':54B,169C,172C,246C 'version':189C,204C,212C 'volumeattribut':49B,164C 'workaround':227C","nicknames":[],"mitigations":[],"who_affected":"Kubernetes clusters running the Amazon EFS CSI Driver between `v3.1.0` and `v3.4.2` are exposed, and the risk is greatest where tenants or untrusted users can create PersistentVolumes or StorageClasses. Clusters on a patched driver, or where only administrators control volume creation, are less exposed. The sources do not say whether non-EFS deployments are affected.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":null,"kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"lab","external_id":"https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/#GHSA-pv26-6q9q-5773","url":"https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-24T18:43:45+00:00","fetched_at":"2026-10-24T18:43:45+00:00","note":"AWS: CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver"}],"documents":[{"id":2887,"url":"https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/","title":"AWS: CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver","kind":"advisory","source":"lab","text":"CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver\n\n### CVE-2026-103505 - Mount Option Injection in Amazon EFS CSI Driver\n\nBulletin ID: 2026-120-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/01/2026 08:30 AM PDT\n\nDescription:\n\nThe 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.\n\nImpacted versions: >= v3.1.0 AND <= v3.4.2\n\nResolution:\n\nThis 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.\n\nWorkarounds:\n\nRestrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC, preventing untrusted users from supplying arbitrary field values.\n\nReferences:\n\n- CVE-2026-103505\n- GHSA-pv26-6q9q-5773\n\n Please email aws-security@amazon.com with any security questions or concerns..","published_at":null,"relation":"advisory","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}