Vulnerability-Lookup

FKIE_CVE-2026-93099

Vulnerability from fkie_nvd - Published: 2026-09-17 17:18 - Updated: 2026-09-17 17:18

Severity

Summary

In the Linux kernel, the following vulnerability has been resolved: fs/resctrl: Fix UAF from worker threads when domains are removed The mbm_handle_overflow() and cqm_handle_limbo() workers read event counters and may sleep while doing so. They are scheduled via delayed_work embedded in struct rdt_l3_mon_domain. Architecture allocates and frees these domains from CPU hotplug callbacks under cpus_write_lock(), and the workers acquire cpus_read_lock() to keep the domain alive across their access. A use-after-free can occur when a worker is blocked waiting for cpus_read_lock() while the hotplug core holds cpus_write_lock(): the architecture frees the rdt_l3_mon_domain that contains the worker's work_struct. When the worker unblocks, the container_of() it performs on the embedded work pointer dereferences freed memory. Drop cpus_read_lock() from the workers and instead drain pending and in-flight work synchronously before the architecture can free the domain. Since architecture offlines the domain under cpus_write_lock() after it has been unlinked from the RCU list and a grace period has elapsed, no new work can be scheduled. The cancel only needs to wait out existing work. Drop rdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that a worker waiting on the mutex can complete before re-pinning the work on a different CPU. When offlining a CPU the architecture may iterate over resources in any order. For example, the MBA control domain may be offlined before or after a corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers no matter what order the architecture offlines the domains.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2566b5cd6a275c124e8f154fef6e815f92ec8d5c
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b86dbfe4583bf134932a6cc45bf25b12c10a0b2f

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/monitor.c",
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b86dbfe4583bf134932a6cc45bf25b12c10a0b2f",
              "status": "affected",
              "version": "24247aeeabe99eab13b798ccccc2dec066dd6f07",
              "versionType": "git"
            },
            {
              "lessThan": "2566b5cd6a275c124e8f154fef6e815f92ec8d5c",
              "status": "affected",
              "version": "24247aeeabe99eab13b798ccccc2dec066dd6f07",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/monitor.c",
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.14"
            },
            {
              "lessThan": "4.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "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\nfs/resctrl: Fix UAF from worker threads when domains are removed\n\nThe mbm_handle_overflow() and cqm_handle_limbo() workers read event counters\nand may sleep while doing so. They are scheduled via delayed_work embedded in\nstruct rdt_l3_mon_domain. Architecture allocates and frees these domains from\nCPU hotplug callbacks under cpus_write_lock(), and the workers acquire\ncpus_read_lock() to keep the domain alive across their access.\n\nA use-after-free can occur when a worker is blocked waiting for\ncpus_read_lock() while the hotplug core holds cpus_write_lock(): the\narchitecture frees the rdt_l3_mon_domain that contains the worker\u0027s\nwork_struct. When the worker unblocks, the container_of() it performs on the\nembedded work pointer dereferences freed memory.\n\nDrop cpus_read_lock() from the workers and instead drain pending and in-flight\nwork synchronously before the architecture can free the domain.  Since\narchitecture offlines the domain under cpus_write_lock() after it has been\nunlinked from the RCU list and a grace period has elapsed, no new work can be\nscheduled. The cancel only needs to wait out existing work.  Drop\nrdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that\na worker waiting on the mutex can complete before re-pinning the work on\na different CPU.\n\nWhen offlining a CPU the architecture may iterate over resources in any order.\nFor example, the MBA control domain may be offlined before or after\na corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers\nno matter what order the architecture offlines the domains."
    }
  ],
  "id": "CVE-2026-93099",
  "lastModified": "2026-09-17T17:18:04.110",
  "metrics": {},
  "published": "2026-09-17T17:18:04.110",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/2566b5cd6a275c124e8f154fef6e815f92ec8d5c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/b86dbfe4583bf134932a6cc45bf25b12c10a0b2f"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-93099 (GCVE-0-2026-93099)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:11 – Updated: 2026-09-17 16:11

Title

fs/resctrl: Fix UAF from worker threads when domains are removed

Summary

Severity

No CVSS data available.

Assigner

Linux mitre root

References

2 references

URL	Tags
https://git.kernel.org/stable/c/b86dbfe4583bf1349…
https://git.kernel.org/stable/c/2566b5cd6a275c124…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 24247aeeabe99eab13b798ccccc2dec066dd6f07 , < b86dbfe4583bf134932a6cc45bf25b12c10a0b2f (git) Affected: 24247aeeabe99eab13b798ccccc2dec066dd6f07 , < 2566b5cd6a275c124e8f154fef6e815f92ec8d5c (git)
Linux	Linux	Affected: 4.14 Unaffected: 0 , < 4.14 (semver) Unaffected: 7.2.6 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/monitor.c",
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "b86dbfe4583bf134932a6cc45bf25b12c10a0b2f",
              "status": "affected",
              "version": "24247aeeabe99eab13b798ccccc2dec066dd6f07",
              "versionType": "git"
            },
            {
              "lessThan": "2566b5cd6a275c124e8f154fef6e815f92ec8d5c",
              "status": "affected",
              "version": "24247aeeabe99eab13b798ccccc2dec066dd6f07",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/resctrl/monitor.c",
            "fs/resctrl/rdtgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.14"
            },
            {
              "lessThan": "4.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3-rc1",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfs/resctrl: Fix UAF from worker threads when domains are removed\n\nThe mbm_handle_overflow() and cqm_handle_limbo() workers read event counters\nand may sleep while doing so. They are scheduled via delayed_work embedded in\nstruct rdt_l3_mon_domain. Architecture allocates and frees these domains from\nCPU hotplug callbacks under cpus_write_lock(), and the workers acquire\ncpus_read_lock() to keep the domain alive across their access.\n\nA use-after-free can occur when a worker is blocked waiting for\ncpus_read_lock() while the hotplug core holds cpus_write_lock(): the\narchitecture frees the rdt_l3_mon_domain that contains the worker\u0027s\nwork_struct. When the worker unblocks, the container_of() it performs on the\nembedded work pointer dereferences freed memory.\n\nDrop cpus_read_lock() from the workers and instead drain pending and in-flight\nwork synchronously before the architecture can free the domain.  Since\narchitecture offlines the domain under cpus_write_lock() after it has been\nunlinked from the RCU list and a grace period has elapsed, no new work can be\nscheduled. The cancel only needs to wait out existing work.  Drop\nrdtgroup_mutex during CPU offline around cancel_delayed_work_sync() so that\na worker waiting on the mutex can complete before re-pinning the work on\na different CPU.\n\nWhen offlining a CPU the architecture may iterate over resources in any order.\nFor example, the MBA control domain may be offlined before or after\na corresponding L3 monitor domain. Ensure that resctrl fs cancels the workers\nno matter what order the architecture offlines the domains."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-17T16:11:12.373Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/b86dbfe4583bf134932a6cc45bf25b12c10a0b2f"
        },
        {
          "url": "https://git.kernel.org/stable/c/2566b5cd6a275c124e8f154fef6e815f92ec8d5c"
        }
      ],
      "title": "fs/resctrl: Fix UAF from worker threads when domains are removed",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-93099",
    "datePublished": "2026-09-17T16:11:12.373Z",
    "dateReserved": "2026-09-17T16:02:15.084Z",
    "dateUpdated": "2026-09-17T16:11:12.373Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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