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FKIE_CVE-2026-74363

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: fix UAF by restoring RCU-delayed inode freeing in bpffs commit 4f375ade6aa9 ("bpf: Avoid RCU context warning when unpinning htab with internal structs") moved inode cleanup from ->free_inode() into ->destroy_inode() to avoid sleeping in RCU context when calling bpf_any_put(). However this removed the RCU delay on freeing the inode itself and the cached symlink body (i_link), both of which can be accessed by RCU pathwalk (pick_link, may_lookup etc.). This causes a use-after-free when a concurrent unlinkat() drops the last inode reference and destroy_inode() frees the inode immediately, while another task is still walking the path in RCU mode and reads inode->i_opflags (offset +2) inside current_time() -> is_mgtime(). KASAN reports: BUG: KASAN: slab-use-after-free in is_mgtime include/linux/fs.h:2313 Read of size 2 at addr ffff8880407e4282 (offset +2 = i_opflags) The rules (per Al Viro): ->destroy_inode() called immediately, can sleep, use for blocking cleanup e.g. bpf_any_put() ->free_inode() called after RCU grace period, use for freeing inode and anything RCU-accessible e.g. i_link Fix: split the two concerns properly: - keep bpf_any_put() in bpf_destroy_inode() since it is blocking and needs to run promptly - introduce bpf_free_inode() to handle kfree(i_link) and free_inode_nonrcu() with proper RCU delay, preventing the UAF
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ea1c243c39e32b7fc1c2edfe32081ff7e30a877c",
              "status": "affected",
              "version": "e28616ca3d67e745ecb2f10eba4a626e1fc9a203",
              "versionType": "git"
            },
            {
              "lessThan": "5fecb71c10c28aef276ba49c718dc961745fdcf0",
              "status": "affected",
              "version": "743a620c661994c7f0938e6dd32fb0883fb1e0ea",
              "versionType": "git"
            },
            {
              "lessThan": "c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2",
              "status": "affected",
              "version": "b6e9645be9eb93f7aff3ca887f8edb6f1d63358f",
              "versionType": "git"
            },
            {
              "lessThan": "53649846e0437d1d9b7cb993cfe54c367addf7ae",
              "status": "affected",
              "version": "ee04cff9ed4d6bb25802f5cecfcd0750500410f3",
              "versionType": "git"
            },
            {
              "lessThan": "61f19729728243c82476dee31315143ed3275e7f",
              "status": "affected",
              "version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
              "versionType": "git"
            },
            {
              "lessThan": "0497ff765746d9b2d17445c8f7cc737b36c0152a",
              "status": "affected",
              "version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
              "versionType": "git"
            },
            {
              "lessThan": "b93c55b4932dd7e32dca8cf34a3443cc87a02906",
              "status": "affected",
              "version": "4f375ade6aa9f37fd72d7a78682f639772089eed",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "de2d2baecc84cc7fca52eec2b9b55d89c93e3565",
              "versionType": "git"
            },
            {
              "lessThan": "5.15.212",
              "status": "affected",
              "version": "5.15.195",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.157",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.113",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.97",
              "status": "affected",
              "version": "6.12.54",
              "versionType": "semver"
            },
            {
              "lessThan": "6.18",
              "status": "affected",
              "version": "6.17.4",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: fix UAF by restoring RCU-delayed inode freeing in bpffs\n\ncommit 4f375ade6aa9 (\"bpf: Avoid RCU context warning when unpinning\nhtab with internal structs\") moved inode cleanup from -\u003efree_inode()\ninto -\u003edestroy_inode() to avoid sleeping in RCU context when calling\nbpf_any_put(). However this removed the RCU delay on freeing the\ninode itself and the cached symlink body (i_link), both of which\ncan be accessed by RCU pathwalk (pick_link, may_lookup etc.).\n\nThis causes a use-after-free when a concurrent unlinkat() drops the\nlast inode reference and destroy_inode() frees the inode immediately,\nwhile another task is still walking the path in RCU mode and reads\ninode-\u003ei_opflags (offset +2) inside current_time() -\u003e is_mgtime().\n\nKASAN reports:\n  BUG: KASAN: slab-use-after-free in is_mgtime include/linux/fs.h:2313\n  Read of size 2 at addr ffff8880407e4282 (offset +2 = i_opflags)\n\nThe rules (per Al Viro):\n  -\u003edestroy_inode()  called immediately, can sleep, use for blocking\n                     cleanup e.g. bpf_any_put()\n  -\u003efree_inode()     called after RCU grace period, use for freeing\n                     inode and anything RCU-accessible e.g. i_link\n\nFix: split the two concerns properly:\n  - keep bpf_any_put() in bpf_destroy_inode() since it is blocking\n    and needs to run promptly\n  - introduce bpf_free_inode() to handle kfree(i_link) and\n    free_inode_nonrcu() with proper RCU delay, preventing the UAF"
    }
  ],
  "id": "CVE-2026-74363",
  "lastModified": "2026-08-17T06:19:31.050",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:22:37.900",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0497ff765746d9b2d17445c8f7cc737b36c0152a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/53649846e0437d1d9b7cb993cfe54c367addf7ae"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5fecb71c10c28aef276ba49c718dc961745fdcf0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/61f19729728243c82476dee31315143ed3275e7f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b93c55b4932dd7e32dca8cf34a3443cc87a02906"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c70d0f9114c3cc156f6029a400c4eb7e6f7c82b2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ea1c243c39e32b7fc1c2edfe32081ff7e30a877c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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