CVE-2026-93810 (GCVE-0-2026-93810)
Vulnerability from cvelistv5
Published
2026-09-24 16:02
Modified
2026-10-03 10:57
Severity ?
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: cachefiles: Fix double fput Fix a double fput() in error handling in cachefiles_create_tmpfile().
References
Impacted products
Vendor Product Version
Linux Linux Version: 24a81759b65fa85767739999d91523691c5e2ea5
Version: 24a81759b65fa85767739999d91523691c5e2ea5
Version: 24a81759b65fa85767739999d91523691c5e2ea5
Version: 24a81759b65fa85767739999d91523691c5e2ea5
Version: 24a81759b65fa85767739999d91523691c5e2ea5
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/cachefiles/namei.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "e582a3e99584d5a634a3cbce4b12e9381fd5d964",
              "status": "affected",
              "version": "24a81759b65fa85767739999d91523691c5e2ea5",
              "versionType": "git"
            },
            {
              "lessThan": "246098a2b8e88761e92cf82c1be1ec576437b176",
              "status": "affected",
              "version": "24a81759b65fa85767739999d91523691c5e2ea5",
              "versionType": "git"
            },
            {
              "lessThan": "e9c2e68c3890a935abbd5f54dbce653f9a16836c",
              "status": "affected",
              "version": "24a81759b65fa85767739999d91523691c5e2ea5",
              "versionType": "git"
            },
            {
              "lessThan": "90b306eee037d0a6a8f4aac834b46e05c5ddd0bf",
              "status": "affected",
              "version": "24a81759b65fa85767739999d91523691c5e2ea5",
              "versionType": "git"
            },
            {
              "lessThan": "af6830cc12dfe86c832dccc9c9878a93aaa22f83",
              "status": "affected",
              "version": "24a81759b65fa85767739999d91523691c5e2ea5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/cachefiles/namei.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.1"
            },
            {
              "lessThan": "6.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.111",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.53",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.111",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.53",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncachefiles: Fix double fput\n\nFix a double fput() in error handling in cachefiles_create_tmpfile()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The extra fput is in cachefiles_create_tmpfile(), reached from nfs_fscache_open_file() (or CIFS/9p/AFS/Ceph fscache_use_cookie()) \u2192 fscache_perform_lookup() \u2192 cachefiles_lookup_cookie() \u2192 cachefiles_look_up_object() \u2192 cachefiles_create_file(), or from cachefiles_invalidate_cookie(); a local open/inval of an fscache-backed file is the entry, not a remote protocol message.\nAC:H - The double fput runs only when kernel_tmpfile_open()\u0027s file has a NULL f_op-\u003eread_iter or f_op-\u003ewrite_iter. cachefiles_add_cache() requires tmpfile/xattr/sync_fs and s_blocksize\u003c=PAGE_SIZE but never checks those f_ops; the only in-tree tmpfile FS lacking write_iter is hugetlbfs, which add_cache rejects, so an attacker cannot make a bound ext4/xfs/btrfs/f2fs tmpfile take this branch.\nPR:L - nfs_fscache_open_file() and the sibling fscache_use_cookie() open paths have no capable() check, so an unprivileged user with read access on an already-bound cachefiles/fscache mount drives cookie lookup into cachefiles_create_tmpfile(); cachefiles_daemon_open() needs init-namespace CAP_SYS_ADMIN, but that is not this trigger.\nUI:N - The attacker themselves open or invalidate files on the fscache-enabled netfs mount, which queues fscache_perform_lookup() into cachefiles_create_tmpfile(); no other user must mount the volume or issue cachefilesd commands.\nS:U - Double-putting the cache tmpfile\u0027s struct file corrupts host kernel file-refcount and filp_cachep state only; it does not cross a KVM/Xen, IOMMU, or other distinct authority.\nC:H - On the !read_iter/!write_iter branch, cachefiles_create_tmpfile() fput()s then err_unuse calls file_inode(file) and fput()s again. fscache_perform_lookup() runs in a PF_KTHREAD worker so the first put is deferred via delayed_fput_work; a later file_inode() on that pointer is a UAF read of a SLAB_TYPESAFE_BY_RCU struct file.\nI:H - The leftover fput before goto err_unuse is a struct-file double-put: if delayed __fput() has already file_free()\u0027d the tmpfile, the second file_ref_put() writes a recycled filp_cachep object (or an underflowed live ref into the dead zone), a UAF write primitive against struct file.\nA:H - The second put hits __file_ref_put_badval()\u0027s \"imbalanced put on file reference count\" WARN_ONCE, and if delayed_fput already ran, file_inode()/inode_lock/fput in cachefiles_create_tmpfile() err_unuse dereference freed memory and oops the fscache worker."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-03T10:57:42.502Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/e582a3e99584d5a634a3cbce4b12e9381fd5d964"
        },
        {
          "url": "https://git.kernel.org/stable/c/246098a2b8e88761e92cf82c1be1ec576437b176"
        },
        {
          "url": "https://git.kernel.org/stable/c/e9c2e68c3890a935abbd5f54dbce653f9a16836c"
        },
        {
          "url": "https://git.kernel.org/stable/c/90b306eee037d0a6a8f4aac834b46e05c5ddd0bf"
        },
        {
          "url": "https://git.kernel.org/stable/c/af6830cc12dfe86c832dccc9c9878a93aaa22f83"
        }
      ],
      "title": "cachefiles: Fix double fput",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93810",
    "datePublished": "2026-09-24T16:02:46.426Z",
    "dateReserved": "2026-09-18T17:59:28.790Z",
    "dateUpdated": "2026-10-03T10:57:42.502Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.