GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2026-72080 (GCVE-0-2026-72080)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:52 – Updated: 2026-08-17 05:40
VLAI
Title
fs/resctrl: Fix use-after-free during unmount
Summary
In the Linux kernel, the following vulnerability has been resolved: fs/resctrl: Fix use-after-free during unmount During unmount or failure teardown all mon_data structures that contain monitoring event file private data are freed after which kernfs nodes are removed. However, the RDT_DELETED flag is never set for the statically allocated default resource group. A concurrent reader of an event file associated with the default resource group may, after dropping kernfs active protection, block on rdtgroup_mutex while unmount proceeds to free the file private data and destroy the kernfs node without waiting for the reader. When the mutex is released, the reader wakes up, observes that RDT_DELETED is not set for the default group, and dereferences the already-freed file private data. The scenario can be depicted as follows: CPU0 CPU1 /* * Default resource group's * monitoring data accessible via * kernfs file with kernfs_node::priv * pointing to a struct mon_data. * User opens the file for reading. */ rdtgroup_mondata_show() /* arch encounters fatal error */ rdtgroup_kn_lock_live() resctrl_exit() atomic_inc(&rdtgroup_default.waitcount) cpus_read_lock() kernfs_break_active_protection(kn) mutex_lock(&rdtgroup_mutex) cpus_read_lock() resctrl_fs_teardown() mutex_lock(&rdtgroup_mutex) rmdir_all_sub() mon_put_kn_priv() /* Delete all mon_data structures */ rdtgroup_destroy_root() kernfs_destroy_root() rdtgroup_default.kn = NULL mutex_unlock(&rdtgroup_mutex) /* * rdtgroup_default.flags is empty so * rdtgroup_kn_lock_live() returns * &rdtgroup_default */ md = of->kn->priv; /* md points to freed mon_data */ Set RDT_DELETED for the default group unconditionally since the flag does not lead to the freeing of this statically allocated group. Do not allow a new resctrl mount if there are any waiters on default group of previous mount. A new mount will re-initialize the default group that would appear to waiters from previous mount as though the default group is accessible causing them to access the mon_data structures from the previous mount that have been removed.
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: 2a65660385444e9d9deffe995c71ee20443ef76e , < 7b7bb07efe41bb646a93c4624aa2bb35df190342 (git)
Affected: 2a65660385444e9d9deffe995c71ee20443ef76e , < 7d330a1d663381579b9d5dafa642b1b3158a0ce2 (git)
Affected: 2a65660385444e9d9deffe995c71ee20443ef76e , < 52fce648607e0d6a76eeb443d78708c49df1c554 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.42 , ≤ 6.18.* (semver)
Unaffected: 7.1.5 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "7b7bb07efe41bb646a93c4624aa2bb35df190342",
              "status": "affected",
              "version": "2a65660385444e9d9deffe995c71ee20443ef76e",
              "versionType": "git"
            },
            {
              "lessThan": "7d330a1d663381579b9d5dafa642b1b3158a0ce2",
              "status": "affected",
              "version": "2a65660385444e9d9deffe995c71ee20443ef76e",
              "versionType": "git"
            },
            {
              "lessThan": "52fce648607e0d6a76eeb443d78708c49df1c554",
              "status": "affected",
              "version": "2a65660385444e9d9deffe995c71ee20443ef76e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.16"
            },
            {
              "lessThan": "6.16",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.42",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "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": "6.18.42",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.5",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.16",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/resctrl: Fix use-after-free during unmount\n\nDuring unmount or failure teardown all mon_data structures that contain\nmonitoring event file private data are freed after which kernfs nodes are\nremoved. However, the RDT_DELETED flag is never set for the statically\nallocated default resource group.\n\nA concurrent reader of an event file associated with the default resource\ngroup may, after dropping kernfs active protection, block on rdtgroup_mutex\nwhile unmount proceeds to free the file private data and destroy the kernfs\nnode without waiting for the reader.\n\nWhen the mutex is released, the reader wakes up, observes that RDT_DELETED\nis not set for the default group, and dereferences the already-freed\nfile private data.\n\nThe scenario can be depicted as follows:\n  CPU0                                      CPU1\n   /*\n    * Default resource group\u0027s\n    * monitoring data accessible via\n    * kernfs file with kernfs_node::priv\n    * pointing to a struct mon_data.\n    * User opens the file for reading.\n    */\n   rdtgroup_mondata_show()                 /* arch encounters fatal error */\n    rdtgroup_kn_lock_live()                 resctrl_exit()\n     atomic_inc(\u0026rdtgroup_default.waitcount) cpus_read_lock()\n     kernfs_break_active_protection(kn)      mutex_lock(\u0026rdtgroup_mutex)\n     cpus_read_lock()                        resctrl_fs_teardown()\n     mutex_lock(\u0026rdtgroup_mutex)              rmdir_all_sub()\n                                              mon_put_kn_priv()\n                                               /* Delete all mon_data structures */\n                                              rdtgroup_destroy_root()\n                                               kernfs_destroy_root()\n                                               rdtgroup_default.kn = NULL\n                                             mutex_unlock(\u0026rdtgroup_mutex)\n     /*\n      * rdtgroup_default.flags is empty so\n      * rdtgroup_kn_lock_live() returns\n      * \u0026rdtgroup_default\n      */\n     md = of-\u003ekn-\u003epriv;\n\n     /* md points to freed mon_data */\n\nSet RDT_DELETED for the default group unconditionally since the flag does\nnot lead to the freeing of this statically allocated group.\n\nDo not allow a new resctrl mount if there are any waiters on default group\nof previous mount. A new mount will re-initialize the default group that\nwould appear to waiters from previous mount as though the default group is\naccessible causing them to access the mon_data structures from the previous\nmount that have been removed."
        }
      ],
      "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 by a local process reading resctrl monitoring event files under /sys/fs/resctrl via open/read on kernfs; there is no network, Bluetooth, or physical-device entry path to rdtgroup_mondata_show().\nAC:L - This is a race between a reader in rdtgroup_kn_lock_live() and teardown in resctrl_fs_teardown()/resctrl_exit(); an attacker can drive both sides with concurrent threads (read mondata while unmounting or during MPAM-initiated teardown) and retry until the window is hit.\nPR:L - Default-group mondata files are world-readable (0444) once resctrl is mounted; triggering teardown via umount is reachable with CAP_SYS_ADMIN from an unprivileged user namespace, and on ARM MPAM systems resctrl_exit() can run while any local user is reading.\nUI:N - No victim interaction is required; the attacker opens and reads monitoring files and initiates or times concurrent resctrl unmount/teardown themselves to win the race.\nS:U - Exploitation corrupts kernel heap memory and enables local privilege escalation within the same kernel security authority; it does not cross a VM, container, or IOMMU boundary by itself.\nC:H - Use-after-free of kmalloc\u0027d struct mon_data lets the attacker influence freed object contents; subsequent reads of md-\u003erid, md-\u003edomid, and md-\u003eevt enable arbitrary kernel memory disclosure through mon_event_read().\nI:H - The UAF provides a controllable heap primitive; forged mon_data/evt pointers passed into mon_event_read() and resctrl_arch_mon_ctx_alloc() can be leveraged for arbitrary kernel writes and local code execution.\nA:H - Dereferencing freed mon_data during rdtgroup_mondata_show() can immediately kernel oops/panic the system, and repeated triggering of the race provides a reliable denial-of-service even before full exploitation."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:40:04.208Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/7b7bb07efe41bb646a93c4624aa2bb35df190342"
        },
        {
          "url": "https://git.kernel.org/stable/c/7d330a1d663381579b9d5dafa642b1b3158a0ce2"
        },
        {
          "url": "https://git.kernel.org/stable/c/52fce648607e0d6a76eeb443d78708c49df1c554"
        }
      ],
      "title": "fs/resctrl: Fix use-after-free during unmount",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-72080",
    "datePublished": "2026-08-15T05:52:29.827Z",
    "dateReserved": "2026-08-09T03:40:39.904Z",
    "dateUpdated": "2026-08-17T05:40:04.208Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-72080",
      "date": "2026-09-04",
      "epss": "0.00168",
      "percentile": "0.06389"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-72080\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-15T06:21:18.027\",\"lastModified\":\"2026-08-17T06:18:06.710\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nfs/resctrl: Fix use-after-free during unmount\\n\\nDuring unmount or failure teardown all mon_data structures that contain\\nmonitoring event file private data are freed after which kernfs nodes are\\nremoved. However, the RDT_DELETED flag is never set for the statically\\nallocated default resource group.\\n\\nA concurrent reader of an event file associated with the default resource\\ngroup may, after dropping kernfs active protection, block on rdtgroup_mutex\\nwhile unmount proceeds to free the file private data and destroy the kernfs\\nnode without waiting for the reader.\\n\\nWhen the mutex is released, the reader wakes up, observes that RDT_DELETED\\nis not set for the default group, and dereferences the already-freed\\nfile private data.\\n\\nThe scenario can be depicted as follows:\\n  CPU0                                      CPU1\\n   /*\\n    * Default resource group\u0027s\\n    * monitoring data accessible via\\n    * kernfs file with kernfs_node::priv\\n    * pointing to a struct mon_data.\\n    * User opens the file for reading.\\n    */\\n   rdtgroup_mondata_show()                 /* arch encounters fatal error */\\n    rdtgroup_kn_lock_live()                 resctrl_exit()\\n     atomic_inc(\u0026rdtgroup_default.waitcount) cpus_read_lock()\\n     kernfs_break_active_protection(kn)      mutex_lock(\u0026rdtgroup_mutex)\\n     cpus_read_lock()                        resctrl_fs_teardown()\\n     mutex_lock(\u0026rdtgroup_mutex)              rmdir_all_sub()\\n                                              mon_put_kn_priv()\\n                                               /* Delete all mon_data structures */\\n                                              rdtgroup_destroy_root()\\n                                               kernfs_destroy_root()\\n                                               rdtgroup_default.kn = NULL\\n                                             mutex_unlock(\u0026rdtgroup_mutex)\\n     /*\\n      * rdtgroup_default.flags is empty so\\n      * rdtgroup_kn_lock_live() returns\\n      * \u0026rdtgroup_default\\n      */\\n     md = of-\u003ekn-\u003epriv;\\n\\n     /* md points to freed mon_data */\\n\\nSet RDT_DELETED for the default group unconditionally since the flag does\\nnot lead to the freeing of this statically allocated group.\\n\\nDo not allow a new resctrl mount if there are any waiters on default group\\nof previous mount. A new mount will re-initialize the default group that\\nwould appear to waiters from previous mount as though the default group is\\naccessible causing them to access the mon_data structures from the previous\\nmount that have been removed.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/resctrl/rdtgroup.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"2a65660385444e9d9deffe995c71ee20443ef76e\",\"lessThan\":\"7b7bb07efe41bb646a93c4624aa2bb35df190342\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2a65660385444e9d9deffe995c71ee20443ef76e\",\"lessThan\":\"7d330a1d663381579b9d5dafa642b1b3158a0ce2\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"2a65660385444e9d9deffe995c71ee20443ef76e\",\"lessThan\":\"52fce648607e0d6a76eeb443d78708c49df1c554\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/resctrl/rdtgroup.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"6.16\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"6.16\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.42\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.5\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/52fce648607e0d6a76eeb443d78708c49df1c554\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7b7bb07efe41bb646a93c4624aa2bb35df190342\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7d330a1d663381579b9d5dafa642b1b3158a0ce2\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-17T21:39:02+00:00",
      "cve": "CVE-2026-72080",
      "id": "CVE-2026-72080",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: fs/resctrl: Fix use-after-free during unmount",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-72080.json",
      "version": "3"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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

Author Source Type Date Other

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.


Detection rules are retrieved from Rulezet.