{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "8e5389132ab429604c1a2459b52f0c849a71cc61"
            },
            {
              "fixed": "bac8fb0d60254846f3b56957435dcd870ae12948"
            },
            {
              "fixed": "503d0568a525b168d9aa5ca046ec72fc5477df84"
            },
            {
              "fixed": "a2038514e69371eb493083a6a897ed20fcbb8acb"
            },
            {
              "fixed": "47e434da476b5a8bcd1e6e52ab03c5ee7764ee78"
            },
            {
              "fixed": "539dce1144651f7976fa418e618b0b574bf15eeb"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.13.0"
            },
            {
              "fixed": "6.6.145"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72379.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs: refuse O_TMPFILE creation with an unmapped fsuid or fsgid\n\nvfs_tmpfile() never checked that the caller's fsuid and fsgid map into\nthe filesystem.  On an idmapped mount whose idmapping does not cover the\ncaller's fs{u,g}id, the -\u003etmpfile() instance initializes the new inode\nthrough inode_init_owner(), where mapped_fsuid()/mapped_fsgid() return\nINVALID_UID/INVALID_GID, and the tmpfile ends up owned by (uid_t)-1.\n\nEvery other creation path already refuses this: may_o_create() (O_CREAT)\nand may_create_dentry() (mkdir, mknod, symlink, link) bail out with\n-EOVERFLOW via fsuidgid_has_mapping() precisely so that an object cannot\nbe created with an owner the filesystem cannot represent.  An O_TMPFILE\nis no exception: it is created I_LINKABLE and linkat(2) can splice it\ninto the namespace afterwards, so the same guarantee must hold.\n\nAdd the missing fsuidgid_has_mapping() check to vfs_tmpfile().  On a\nnon-idmapped mount the caller's fs{u,g}id always map in the superblock's\nuser namespace, so this is a no-op there and only takes effect on an\nidmapped mount that does not map the caller.  It applies to every\nfilesystem that sets FS_ALLOW_IDMAP and implements -\u003etmpfile() (tmpfs,\next4, btrfs, xfs, f2fs, ...), and to overlayfs, whose upper-layer\ntmpfile creation funnels through vfs_tmpfile() via backing_tmpfile_open().",
  "id": "CVE-2026-72379",
  "modified": "2026-08-16T03:31:14.412856469Z",
  "published": "2026-08-15T05:56:12.251Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/47e434da476b5a8bcd1e6e52ab03c5ee7764ee78"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/503d0568a525b168d9aa5ca046ec72fc5477df84"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/539dce1144651f7976fa418e618b0b574bf15eeb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2038514e69371eb493083a6a897ed20fcbb8acb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bac8fb0d60254846f3b56957435dcd870ae12948"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72379.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72379"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "summary": "fs: refuse O_TMPFILE creation with an unmapped fsuid or fsgid"
}