cvelistv5 - CVE-2025-40209

CVE-2025-40209 (GCVE-0-2025-40209)

Vulnerability from cvelistv5 – Published: 2025-11-21 10:19 – Updated: 2025-12-01 06:20

Title

btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation

Summary

In the Linux kernel, the following vulnerability has been resolved: btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation When btrfs_add_qgroup_relation() is called with invalid qgroup levels (src >= dst), the function returns -EINVAL directly without freeing the preallocated qgroup_list structure passed by the caller. This causes a memory leak because the caller unconditionally sets the pointer to NULL after the call, preventing any cleanup. The issue occurs because the level validation check happens before the mutex is acquired and before any error handling path that would free the prealloc pointer. On this early return, the cleanup code at the 'out' label (which includes kfree(prealloc)) is never reached. In btrfs_ioctl_qgroup_assign(), the code pattern is: prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL); ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc); prealloc = NULL; // Always set to NULL regardless of return value ... kfree(prealloc); // This becomes kfree(NULL), does nothing When the level check fails, 'prealloc' is never freed by either the callee or the caller, resulting in a 64-byte memory leak per failed operation. This can be triggered repeatedly by an unprivileged user with access to a writable btrfs mount, potentially exhausting kernel memory. Fix this by freeing prealloc before the early return, ensuring prealloc is always freed on all error paths.

Severity ?

No CVSS data available.

Assigner

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/3412d0e973e8f8381…
	https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d…
	https://git.kernel.org/stable/c/f260c6aff0b8af236…

Impacted products

Vendor

Product

Version

Linux

Affected: 4addc1ffd67ad34394674dc91379dc04cfdd2537 , < 3412d0e973e8f8381747d69033eda809a57a2581 (git)
Affected: 4addc1ffd67ad34394674dc91379dc04cfdd2537 , < a4d9ebe23bcb79d9d057e3c995db73b7b3aae414 (git)
Affected: 4addc1ffd67ad34394674dc91379dc04cfdd2537 , < f260c6aff0b8af236084012d14f9f1bf792ea883 (git)

Linux

Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.58 , ≤ 6.12.* (semver)
Unaffected: 6.17.8 , ≤ 6.17.* (semver)
Unaffected: 6.18 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/qgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3412d0e973e8f8381747d69033eda809a57a2581",
              "status": "affected",
              "version": "4addc1ffd67ad34394674dc91379dc04cfdd2537",
              "versionType": "git"
            },
            {
              "lessThan": "a4d9ebe23bcb79d9d057e3c995db73b7b3aae414",
              "status": "affected",
              "version": "4addc1ffd67ad34394674dc91379dc04cfdd2537",
              "versionType": "git"
            },
            {
              "lessThan": "f260c6aff0b8af236084012d14f9f1bf792ea883",
              "status": "affected",
              "version": "4addc1ffd67ad34394674dc91379dc04cfdd2537",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/btrfs/qgroup.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.58",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.17.*",
              "status": "unaffected",
              "version": "6.17.8",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.18",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.58",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.17.8",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation\n\nWhen btrfs_add_qgroup_relation() is called with invalid qgroup levels\n(src \u003e= dst), the function returns -EINVAL directly without freeing the\npreallocated qgroup_list structure passed by the caller. This causes a\nmemory leak because the caller unconditionally sets the pointer to NULL\nafter the call, preventing any cleanup.\n\nThe issue occurs because the level validation check happens before the\nmutex is acquired and before any error handling path that would free\nthe prealloc pointer. On this early return, the cleanup code at the\n\u0027out\u0027 label (which includes kfree(prealloc)) is never reached.\n\nIn btrfs_ioctl_qgroup_assign(), the code pattern is:\n\n    prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);\n    ret = btrfs_add_qgroup_relation(trans, sa-\u003esrc, sa-\u003edst, prealloc);\n    prealloc = NULL;  // Always set to NULL regardless of return value\n    ...\n    kfree(prealloc);  // This becomes kfree(NULL), does nothing\n\nWhen the level check fails, \u0027prealloc\u0027 is never freed by either the\ncallee or the caller, resulting in a 64-byte memory leak per failed\noperation. This can be triggered repeatedly by an unprivileged user\nwith access to a writable btrfs mount, potentially exhausting kernel\nmemory.\n\nFix this by freeing prealloc before the early return, ensuring prealloc\nis always freed on all error paths."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-12-01T06:20:14.073Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/3412d0e973e8f8381747d69033eda809a57a2581"
        },
        {
          "url": "https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d057e3c995db73b7b3aae414"
        },
        {
          "url": "https://git.kernel.org/stable/c/f260c6aff0b8af236084012d14f9f1bf792ea883"
        }
      ],
      "title": "btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-40209",
    "datePublished": "2025-11-21T10:19:44.757Z",
    "dateReserved": "2025-04-16T07:20:57.179Z",
    "dateUpdated": "2025-12-01T06:20:14.073Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-40209\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-11-21T11:15:47.000\",\"lastModified\":\"2025-11-21T15:13:13.800\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbtrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation\\n\\nWhen btrfs_add_qgroup_relation() is called with invalid qgroup levels\\n(src \u003e= dst), the function returns -EINVAL directly without freeing the\\npreallocated qgroup_list structure passed by the caller. This causes a\\nmemory leak because the caller unconditionally sets the pointer to NULL\\nafter the call, preventing any cleanup.\\n\\nThe issue occurs because the level validation check happens before the\\nmutex is acquired and before any error handling path that would free\\nthe prealloc pointer. On this early return, the cleanup code at the\\n\u0027out\u0027 label (which includes kfree(prealloc)) is never reached.\\n\\nIn btrfs_ioctl_qgroup_assign(), the code pattern is:\\n\\n    prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);\\n    ret = btrfs_add_qgroup_relation(trans, sa-\u003esrc, sa-\u003edst, prealloc);\\n    prealloc = NULL;  // Always set to NULL regardless of return value\\n    ...\\n    kfree(prealloc);  // This becomes kfree(NULL), does nothing\\n\\nWhen the level check fails, \u0027prealloc\u0027 is never freed by either the\\ncallee or the caller, resulting in a 64-byte memory leak per failed\\noperation. This can be triggered repeatedly by an unprivileged user\\nwith access to a writable btrfs mount, potentially exhausting kernel\\nmemory.\\n\\nFix this by freeing prealloc before the early return, ensuring prealloc\\nis always freed on all error paths.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/3412d0e973e8f8381747d69033eda809a57a2581\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d057e3c995db73b7b3aae414\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f260c6aff0b8af236084012d14f9f1bf792ea883\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}

FKIE_CVE-2025-40209

Vulnerability from fkie_nvd - Published: 2025-11-21 11:15 - Updated: 2025-11-21 15:13

Severity ?

Summary

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/3412d0e973e8f8381747d69033eda809a57a2581
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d057e3c995db73b7b3aae414
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/f260c6aff0b8af236084012d14f9f1bf792ea883

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation\n\nWhen btrfs_add_qgroup_relation() is called with invalid qgroup levels\n(src \u003e= dst), the function returns -EINVAL directly without freeing the\npreallocated qgroup_list structure passed by the caller. This causes a\nmemory leak because the caller unconditionally sets the pointer to NULL\nafter the call, preventing any cleanup.\n\nThe issue occurs because the level validation check happens before the\nmutex is acquired and before any error handling path that would free\nthe prealloc pointer. On this early return, the cleanup code at the\n\u0027out\u0027 label (which includes kfree(prealloc)) is never reached.\n\nIn btrfs_ioctl_qgroup_assign(), the code pattern is:\n\n    prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);\n    ret = btrfs_add_qgroup_relation(trans, sa-\u003esrc, sa-\u003edst, prealloc);\n    prealloc = NULL;  // Always set to NULL regardless of return value\n    ...\n    kfree(prealloc);  // This becomes kfree(NULL), does nothing\n\nWhen the level check fails, \u0027prealloc\u0027 is never freed by either the\ncallee or the caller, resulting in a 64-byte memory leak per failed\noperation. This can be triggered repeatedly by an unprivileged user\nwith access to a writable btrfs mount, potentially exhausting kernel\nmemory.\n\nFix this by freeing prealloc before the early return, ensuring prealloc\nis always freed on all error paths."
    }
  ],
  "id": "CVE-2025-40209",
  "lastModified": "2025-11-21T15:13:13.800",
  "metrics": {},
  "published": "2025-11-21T11:15:47.000",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3412d0e973e8f8381747d69033eda809a57a2581"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d057e3c995db73b7b3aae414"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f260c6aff0b8af236084012d14f9f1bf792ea883"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}

GHSA-2833-8JVF-3588

Vulnerability from github – Published: 2025-11-21 12:32 – Updated: 2025-11-21 12:32

Details

In the Linux kernel, the following vulnerability has been resolved:

btrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation

When btrfs_add_qgroup_relation() is called with invalid qgroup levels (src >= dst), the function returns -EINVAL directly without freeing the preallocated qgroup_list structure passed by the caller. This causes a memory leak because the caller unconditionally sets the pointer to NULL after the call, preventing any cleanup.

The issue occurs because the level validation check happens before the mutex is acquired and before any error handling path that would free the prealloc pointer. On this early return, the cleanup code at the 'out' label (which includes kfree(prealloc)) is never reached.

In btrfs_ioctl_qgroup_assign(), the code pattern is:

prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);
ret = btrfs_add_qgroup_relation(trans, sa->src, sa->dst, prealloc);
prealloc = NULL;  // Always set to NULL regardless of return value
...
kfree(prealloc);  // This becomes kfree(NULL), does nothing

When the level check fails, 'prealloc' is never freed by either the callee or the caller, resulting in a 64-byte memory leak per failed operation. This can be triggered repeatedly by an unprivileged user with access to a writable btrfs mount, potentially exhausting kernel memory.

Fix this by freeing prealloc before the early return, ensuring prealloc is always freed on all error paths.

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2025-40209"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-11-21T11:15:47Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix memory leak of qgroup_list in btrfs_add_qgroup_relation\n\nWhen btrfs_add_qgroup_relation() is called with invalid qgroup levels\n(src \u003e= dst), the function returns -EINVAL directly without freeing the\npreallocated qgroup_list structure passed by the caller. This causes a\nmemory leak because the caller unconditionally sets the pointer to NULL\nafter the call, preventing any cleanup.\n\nThe issue occurs because the level validation check happens before the\nmutex is acquired and before any error handling path that would free\nthe prealloc pointer. On this early return, the cleanup code at the\n\u0027out\u0027 label (which includes kfree(prealloc)) is never reached.\n\nIn btrfs_ioctl_qgroup_assign(), the code pattern is:\n\n    prealloc = kzalloc(sizeof(*prealloc), GFP_KERNEL);\n    ret = btrfs_add_qgroup_relation(trans, sa-\u003esrc, sa-\u003edst, prealloc);\n    prealloc = NULL;  // Always set to NULL regardless of return value\n    ...\n    kfree(prealloc);  // This becomes kfree(NULL), does nothing\n\nWhen the level check fails, \u0027prealloc\u0027 is never freed by either the\ncallee or the caller, resulting in a 64-byte memory leak per failed\noperation. This can be triggered repeatedly by an unprivileged user\nwith access to a writable btrfs mount, potentially exhausting kernel\nmemory.\n\nFix this by freeing prealloc before the early return, ensuring prealloc\nis always freed on all error paths.",
  "id": "GHSA-2833-8jvf-3588",
  "modified": "2025-11-21T12:32:23Z",
  "published": "2025-11-21T12:32:23Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-40209"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3412d0e973e8f8381747d69033eda809a57a2581"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a4d9ebe23bcb79d9d057e3c995db73b7b3aae414"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f260c6aff0b8af236084012d14f9f1bf792ea883"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

Sightings

Author	Source	Type	Date

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.

Action not permitted

CVE-2025-40209 (GCVE-0-2025-40209)

FKIE_CVE-2025-40209

GHSA-2833-8JVF-3588

Tags

Sightings

Nomenclature