CVE-2026-99111

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix data corruption with concurrent writes and O_TRUNC cifs_do_truncate() flushes dirty pages with filemap_write_and_wait() and truncates the file on the server, but in the old code both operations ran without holding i_rwsem or invalidate_lock. A concurrent buffered write via netfs_perform_write() -- which only needs i_rwsem shared -- could dirty new pages after the flush but before the local truncation, and those pages would be silently discarded by cifs_setsize() -> truncate_pagecache(). Fix by acquiring inode_lock (exclusive i_rwsem) and filemap_invalidate_lock at the top of cifs_do_truncate(), so the entire flush-truncate-resize sequence is atomic with respect to: - buffered writes (blocked by exclusive i_rwsem, since netfs_start_io_write takes i_rwsem shared), - read page faults (blocked by exclusive invalidate_lock, since filemap_fault takes it shared), - writeback collection (blocked by netfs_wb_begin/netfs_wb_end around the server truncate and local resize, since netfs_writepages also acquires the wb lock).

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-10-28 11:17:30.520000

Last modified

2026-10-28 11:17:30.520000

View original CVE JSON

{
  "id": "CVE-2026-99111",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-28T11:17:30.520",
  "lastModified": "2026-10-28T11:17:30.520",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix data corruption with concurrent writes and O_TRUNC\n\ncifs_do_truncate() flushes dirty pages with filemap_write_and_wait()\nand truncates the file on the server, but in the old code both\noperations ran without holding i_rwsem or invalidate_lock.  A\nconcurrent buffered write via netfs_perform_write() -- which only\nneeds i_rwsem shared -- could dirty new pages after the flush but\nbefore the local truncation, and those pages would be silently\ndiscarded by cifs_setsize() -> truncate_pagecache().\n\nFix by acquiring inode_lock (exclusive i_rwsem) and\nfilemap_invalidate_lock at the top of cifs_do_truncate(), so the\nentire flush-truncate-resize sequence is atomic with respect to:\n\n  - buffered writes (blocked by exclusive i_rwsem, since\n    netfs_start_io_write takes i_rwsem shared),\n  - read page faults (blocked by exclusive invalidate_lock, since\n    filemap_fault takes it shared),\n  - writeback collection (blocked by netfs_wb_begin/netfs_wb_end\n    around the server truncate and local resize, since\n    netfs_writepages also acquires the wb lock)."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/smb/client/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
              "lessThan": "4d143608a0445443a85c9b29f4c9f8e63d5dbfc9",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
              "lessThan": "ffa66fdc7d35b890606767c4d2c7ac26b4d90a99",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "110fee6b9bb58a5c50047fc2594d415f741b591e",
              "lessThan": "a8603b52b39f520ea8a34def74c23fba87396d3e",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/smb/client/file.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.18",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.18",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.59",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.13",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/4d143608a0445443a85c9b29f4c9f8e63d5dbfc9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/a8603b52b39f520ea8a34def74c23fba87396d3e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/ffa66fdc7d35b890606767c4d2c7ac26b4d90a99",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}