{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-89605",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-89605"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "ecryptfs: release message context on send failure",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\necryptfs: release message context on send failure\n\necryptfs_send_message_locked() moves a message context from the free\nlist to the allocated list before sending the request to the userspace\ndaemon.\n\nIf ecryptfs_send_miscdev() fails, the context is left on the\nallocated list and cannot be reused. Move it back to the free list on\nfailure and clear the caller's pointer.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-89605"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/177e0c32fec3602bb3b64139bb8bb610cd6722c7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/743e7aeb9575c0838d8996d40d81a6b8fa5cd060"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/590fc6140e29c54d2f7839eb9df78d106ee1905e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/30845ed227475a11a49ccce047837d016b7e0f49"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/47ce611cb13f0eefa550d5434c1afcd4217bfc3e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9319706316a8e79f374627554386d575a84b637f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/654b7e79443f5ea90849f5c1cf70c0d94bd5b10e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/219644a3ad5518217b2d62cad6d2c36a2308c949"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-14T12:06:03Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The bug is reached only via local syscalls: open/creat on an eCryptfs mount drives pki_encrypt_session_key()/decrypt_pki_encrypted_session_key() into ecryptfs_send_message_locked(), and the per-euid daemon is registered with open(/dev/ecryptfs); no network or adjacent protocol path exists.\nAC:L - ecryptfs_send_miscdev() fails only on kmalloc(), which a local attacker in a memory cgroup can force by filling memory.max so the small GFP_KERNEL allocation returns NULL; the attacker then repeats create/open while running the daemon, with no race or other condition outside their control.\nPR:L - Neither miscdev_open() nor the PKI send path checks capabilities. An unprivileged user reaches this by running ecryptfsd on /dev/ecryptfs and using an eCryptfs mount from setuid mount.ecryptfs_private or an existing encrypted home, with a user-keyring PRIVATE_KEY auth token.\nUI:N - The attacker registers their own daemon, installs their own auth token, uses their own eCryptfs directory, and issues the create/open syscalls; no other user needs to mount, open a file, or otherwise interact.\nS:U - The leaked msg_ctx slots and any later use of the dangling msg_ctx->task pointer stay inside the host kernel's eCryptfs messaging subsystem; this is ordinary kernel impact, not a VM, IOMMU, or sandbox escape.\nC:H - A failed send leaves the msg_ctx PENDING with a raw task_struct pointer. After the sender exits, the attacker's daemon can write a MSG_RESPONSE with that index and predictable counter so ecryptfs_process_response() calls wake_up_process() on the freed task, a UAF that discloses kernel memory.\nI:H - The same task_struct use-after-free is heap-sprayable: wake_up_process() writes into a recycled task object and can hijack control flow. Stuck PENDING contexts are also never returned to the 32-slot global pool, breaking eCryptfs messaging for every user.\nA:H - Each failed send permanently removes one of 32 global msg_ctx slots from the free list until reboot, fully denying eCryptfs PKI wrap/unwrap for all users, and the dangling-task wake_up_process() path can oops or panic the kernel."
    }
  }
}