{"id":"CVE-2026-103505","kind":"vulnerability","aliases":["CVE-2026-103505"],"related":[],"title":"AWS EFS CSI Driver: mount option injection via mounttargetipmap volume attribute","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 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.","severity":"medium","cvss":6.9,"epss":0.00432,"exploited":false,"exploited_at":null,"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"],"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.\n- 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`.\n- Restrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC.\n- Patch any forked or derivative copies of the driver code.","status":"open","published_at":"2026-10-01T16:17:36+00:00","first_seen_at":"2026-10-24T18:43:45+00:00","triaged_at":"2026-10-25T03:42:34+00:00","updated_at":"2026-10-25T12:38:49+00:00","category":"infrastructure","confidence":0.8,"triage":{"at":"2026-10-25T03:42:34Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade the Amazon EFS CSI Driver to `v3.5.0`.\n- Restrict PersistentVolume and StorageClass creation to cluster administrators using Kubernetes RBAC.\n- Patch any forked or derivative copies of the driver code.","reach":"local","title":"AWS EFS CSI Driver: mount option injection via mounttargetipmap volume attribute","impact":"medium","summary":"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.","category":"infrastructure","nicknames":[],"who_cares":["kubernetes","aws","eks","storage"],"confidence":0.8,"needs_auth":"yes","worst_case":"Attacker alters EFS mount options on the node, affecting volume mounts","analyst_note":"","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.\n- Check who can create PersistentVolumes and StorageClasses with `kubectl auth can-i create persistentvolumes --all-namespaces` and review the RBAC bindings.","needs_analyst":false,"not_affected_if":["driver-below-v3.1.0-or-above-v3.4.2","only-admins-create-storage-objects"],"who_is_affected":"Clusters running Amazon EFS CSI Driver versions `>= v3.1.0` and `<= v3.4.2` are affected. Exposure depends on whether untrusted users can create PersistentVolumes or StorageClasses that set the mounttargetipmap attribute; clusters where only administrators control storage objects are at much lower risk.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000726,"input_tokens":3805,"output_tokens":690,"severity_before":"medium"},"analyst_status":null,"analyst_note":null,"search":"'-103505':14A,17A,72C,83C,137C,239C '-120':95C '-2026':13A,16A,71C,82C,136C,238C '..':254C '08':107C '10/01/2026':106C '2026':94C '30':108C '5773':244C '6q9q':243C 'actor':140C 'addit':147C 'address':187C 'administr':224C 'allow':124C 'amazon':27B,77C,88C,113C,129C,189C 'append':154C 'arbitrari':233C 'attack':57B 'attent':103C 'attribut':11A 'aw':1A,18B,96C,98C 'aws-security@amazon.com':247C 'bulletin':92C 'caus':166C 'chang':59B 'cluster':126C,223C 'code':208C 'comma':48B,156C 'comma-separ':47B,155C 'concern':253C 'contain':119C 'content':99C 'creat':36B 'creation':143C,221C 'csi':3A,29B,79C,90C,115C,191C 'cve':12A,15A,70C,81C,135C,237C 'date':105C 'deriv':207C 'descript':111C 'disclosur':24B 'driver':4A,30B,80C,91C,116C,122C,192C 'ef':2A,28B,62B,78C,89C,114C,190C 'ek':19B 'elast':130C 'email':246C 'ensur':203C 'extra':39B 'field':234C 'file':131C 'fix':215C 'fork':205C 'ghsa':241C 'ghsa-pv26-6q9q':240C 'id':93C 'identifi':134C 'impact':177C 'import':101C 'incorpor':212C 'infrastructur':20B 'inject':7A,38B,75C,86C,146C 'insid':162C 'interfac':121C 'issu':184C 'json':164C 'kubernet':21B,68B,125C,226C 'lab':23B 'lab-disclosur':22B 'latest':200C 'let':31B 'map':165C 'mount':5A,40B,65B,73C,84C,148C,168C,175C 'mounttargetipmap':9A,44B,152C 'new':214C 'node':69B 'option':6A,41B,55B,74C,85C,149C,176C 'pars':52B,171C 'patch':210C 'pdt':110C 'persistentvolum':37B,142C,218C 'pleas':245C 'prevent':228C 'privileg':144C 'public':104C 'pv26':242C 'question':251C 'rbac':227C 'recommend':196C 'refer':236C 'requir':102C 'resolut':182C 'restrict':217C 'scope':97C 'secur':250C 'separ':49B,54B,157C,174C 'storag':25B,120C 'storageclass':220C 'suppli':232C 'system':132C 'type':100C 'untrust':229C 'upgrad':197C 'use':128C,225C 'user':33B,230C 'util':169C 'v3.1.0':179C 'v3.4.2':181C 'v3.5.0':194C 'valu':50B,158C,161C,235C 'version':178C,193C,201C 'via':8A 'volum':10A,63B 'volumeattribut':45B,153C 'workaround':216C","nicknames":[],"mitigations":[],"who_affected":"Clusters running Amazon EFS CSI Driver versions `>= v3.1.0` and `<= v3.4.2` are affected. Exposure depends on whether untrusted users can create PersistentVolumes or StorageClasses that set the mounttargetipmap attribute; clusters where only administrators control storage objects are at much lower risk.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-01T16:17:36+00:00","kev":null,"cvss_vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:H/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","cvss_by":"ff89ba41-3aa1-4d27-914a-91399e9639e5","poc_count":0,"sources":[{"source":"lab","external_id":"https://aws.amazon.com/security/security-bulletins/rss/2026-120-aws/#CVE-2026-103505","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"},{"source":"nvd","external_id":"CVE-2026-103505","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-103505","severity":null,"published_at":"2026-10-01T16:17:36+00:00","modified_at":"2026-10-02T14:17:07+00:00","first_seen_at":"2026-10-24T18:53:56+00:00","fetched_at":"2026-10-24T18:53:56+00:00","note":null},{"source":"epss","external_id":"CVE-2026-103505","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-103505","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-25T12:38:49+00:00","fetched_at":"2026-10-25T12:38:49+00:00","note":null}],"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"}