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CVE-2026-72372 (GCVE-0-2026-72372)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:56 – Updated: 2026-08-17 05:43
VLAI
Title
afs: Fix lack of locking around modifications of net->cells_dyn_ino
Summary
In the Linux kernel, the following vulnerability has been resolved: afs: Fix lack of locking around modifications of net->cells_dyn_ino Fix the lack of locking around modifications of net->cells_dyn_ino by taking net->cells_lock exclusively. This also requires to cell to be removed from net->cells_dyn_ino in afs_destroy_cell_work() rather than in afs_cell_destroy() as the latter runs in RCU cleanup context and sleeping locks cannot be taken there.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 537b0105952578531f748c7fb3ce36ae9a514784 , < 4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b (git)
Affected: 1d0b929fc070b4115403a0a6206a0c6a62dd61f5 , < 2ffb70a8a01988046bb207b7d0af9358a8337378 (git)
Affected: 1d0b929fc070b4115403a0a6206a0c6a62dd61f5 , < e94f92fd56c553a8bf9421c3289e1b85c7c08857 (git)
Affected: 1d0b929fc070b4115403a0a6206a0c6a62dd61f5 , < 55e841836c6f4646490f7b0347192b7a92d431ba (git)
Affected: 6.12.97 , < 6.12.101 (semver)
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Linux Linux Affected: 6.15
Unaffected: 0 , < 6.15 (semver)
Unaffected: 6.12.101 , ≤ 6.12.* (semver)
Unaffected: 6.18.40 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/afs/cell.c",
            "fs/afs/dynroot.c"
          ],
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          "vendor": "Linux",
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              "versionType": "git"
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              "versionType": "original_commit_for_fix"
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        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.101",
                  "versionStartIncluding": "6.12.97",
                  "vulnerable": true
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                  "versionEndExcluding": "7.2",
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix lack of locking around modifications of net-\u003ecells_dyn_ino\n\nFix the lack of locking around modifications of net-\u003ecells_dyn_ino by\ntaking net-\u003ecells_lock exclusively.  This also requires to cell to be\nremoved from net-\u003ecells_dyn_ino in afs_destroy_cell_work() rather than in\nafs_cell_destroy() as the latter runs in RCU cleanup context and sleeping\nlocks cannot be taken there."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through local VFS operations on an AFS dynroot mount (getdents/readdir via afs_dynroot_readdir, lookup via afs_dynroot_lookup_cell) and cell create/destroy paths (afs_alloc_cell/afs_destroy_cell_work), not from remote AFS/RxRPC packet handling.\nAC:L - An attacker can reliably win the race by running concurrent threads that repeatedly readdir /afs while creating and expiring cells through lookups or /proc/net/afs/cells writes; syzbot and public PoCs reproduced the slab UAF within minutes without uncontrollable layout dependencies.\nPR:L - Exploitation requires only an unprivileged local user who can access a dynroot mount (typical world-readable /afs on AFS clients) or mount AFS with -o dyn inside a user namespace where CAP_SYS_ADMIN is available; real init-namespace root is not required.\nUI:N - No victim interaction is needed once dynroot is available; the attacker directly issues the readdir and cell-creation syscalls that race unsynchronized idr_alloc_cyclic, idr_remove, and idr_get_next on net-\u003ecells_dyn_ino.\nS:U - Impact is confined to kernel memory integrity and privilege boundaries within the host kernel; it does not cross VM, container, or IOMMU security scopes into a different authority.\nC:H - Concurrent idr_remove during afs_dynroot_readdir_cells leaves idr_get_next with a dangling afs_cell pointer, causing slab use-after-free reads of cell-\u003ename and cell-\u003estate (confirmed by KASAN in afs_dynroot_readdir) and enabling further kernel memory disclosure.\nI:H - IDR tree corruption and use-after-free of afs_cell objects provide attacker-influenced heap corruption primitives that can be developed into arbitrary kernel writes or control-flow hijack, not merely a benign error return.\nA:H - The race causes kernel oops/panic from corrupted IDR traversal or use-after-free during dir_emit; repeated triggering can crash or hang the system, satisfying high availability impact."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:43:25.401Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/4d8a2fe8847859f4fa4e9a2fa1221c9c1158e66b"
        },
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          "url": "https://git.kernel.org/stable/c/2ffb70a8a01988046bb207b7d0af9358a8337378"
        },
        {
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        },
        {
          "url": "https://git.kernel.org/stable/c/55e841836c6f4646490f7b0347192b7a92d431ba"
        }
      ],
      "title": "afs: Fix lack of locking around modifications of net-\u003ecells_dyn_ino",
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72372",
    "datePublished": "2026-08-15T05:56:07.916Z",
    "dateReserved": "2026-08-09T03:40:39.922Z",
    "dateUpdated": "2026-08-17T05:43:25.401Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-09-04",
      "epss": "0.00175",
      "percentile": "0.07104"
    },
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T06:42:57+00:00",
      "cve": "CVE-2026-72372",
      "id": "CVE-2026-72372",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "76",
      "product_status:known_not_affected": "198",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: afs: Fix lack of locking around modifications of net-\u003ecells_dyn_ino",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72372.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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