CVE-2025-38457 (GCVE-0-2025-38457)
Vulnerability from cvelistv5
Published
2025-07-25 15:27
Modified
2025-07-28 04:22
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: Abort __tc_modify_qdisc if parent class does not exist Lion's patch [1] revealed an ancient bug in the qdisc API. Whenever a user creates/modifies a qdisc specifying as a parent another qdisc, the qdisc API will, during grafting, detect that the user is not trying to attach to a class and reject. However grafting is performed after qdisc_create (and thus the qdiscs' init callback) is executed. In qdiscs that eventually call qdisc_tree_reduce_backlog during init or change (such as fq, hhf, choke, etc), an issue arises. For example, executing the following commands: sudo tc qdisc add dev lo root handle a: htb default 2 sudo tc qdisc add dev lo parent a: handle beef fq Qdiscs such as fq, hhf, choke, etc unconditionally invoke qdisc_tree_reduce_backlog() in their control path init() or change() which then causes a failure to find the child class; however, that does not stop the unconditional invocation of the assumed child qdisc's qlen_notify with a null class. All these qdiscs make the assumption that class is non-null. The solution is ensure that qdisc_leaf() which looks up the parent class, and is invoked prior to qdisc_create(), should return failure on not finding the class. In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the parentid doesn't correspond to a class, so that we can detect it earlier on and abort before qdisc_create is called. [1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/
References
Impacted products
Vendor Product Version
Linux Linux Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
Version: 5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "923a276c74e25073ae391e930792ac86a9f77f1e",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "90436e72c9622c2f70389070088325a3232d339f",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "25452638f133ac19d75af3f928327d8016952c8e",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "23c165dde88eac405eebb59051ea1fe139a45803",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "4c691d1b6b6dbd73f30ed9ee7da05f037b0c49af",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "8ecd651ef24ab50123692a4e3e25db93cb11602a",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "e28a383d6485c3bb51dc5953552f76c4dea33eea",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            },
            {
              "lessThan": "ffdde7bf5a439aaa1955ebd581f5c64ab1533963",
              "status": "affected",
              "version": "5e50da01d0ce7ef0ba3ed6cfabd62f327da0aca6",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_api.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.20"
            },
            {
              "lessThan": "2.6.20",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.296",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.240",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.146",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.99",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.15.*",
              "status": "unaffected",
              "version": "6.15.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.16",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.296",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.240",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.189",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.146",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.99",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.39",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15.7",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.16",
                  "versionStartIncluding": "2.6.20",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: Abort __tc_modify_qdisc if parent class does not exist\n\nLion\u0027s patch [1] revealed an ancient bug in the qdisc API.\nWhenever a user creates/modifies a qdisc specifying as a parent another\nqdisc, the qdisc API will, during grafting, detect that the user is\nnot trying to attach to a class and reject. However grafting is\nperformed after qdisc_create (and thus the qdiscs\u0027 init callback) is\nexecuted. In qdiscs that eventually call qdisc_tree_reduce_backlog\nduring init or change (such as fq, hhf, choke, etc), an issue\narises. For example, executing the following commands:\n\nsudo tc qdisc add dev lo root handle a: htb default 2\nsudo tc qdisc add dev lo parent a: handle beef fq\n\nQdiscs such as fq, hhf, choke, etc unconditionally invoke\nqdisc_tree_reduce_backlog() in their control path init() or change() which\nthen causes a failure to find the child class; however, that does not stop\nthe unconditional invocation of the assumed child qdisc\u0027s qlen_notify with\na null class. All these qdiscs make the assumption that class is non-null.\n\nThe solution is ensure that qdisc_leaf() which looks up the parent\nclass, and is invoked prior to qdisc_create(), should return failure on\nnot finding the class.\nIn this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the\nparentid doesn\u0027t correspond to a class, so that we can detect it\nearlier on and abort before qdisc_create is called.\n\n[1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-07-28T04:22:51.557Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/923a276c74e25073ae391e930792ac86a9f77f1e"
        },
        {
          "url": "https://git.kernel.org/stable/c/90436e72c9622c2f70389070088325a3232d339f"
        },
        {
          "url": "https://git.kernel.org/stable/c/25452638f133ac19d75af3f928327d8016952c8e"
        },
        {
          "url": "https://git.kernel.org/stable/c/23c165dde88eac405eebb59051ea1fe139a45803"
        },
        {
          "url": "https://git.kernel.org/stable/c/4c691d1b6b6dbd73f30ed9ee7da05f037b0c49af"
        },
        {
          "url": "https://git.kernel.org/stable/c/8ecd651ef24ab50123692a4e3e25db93cb11602a"
        },
        {
          "url": "https://git.kernel.org/stable/c/e28a383d6485c3bb51dc5953552f76c4dea33eea"
        },
        {
          "url": "https://git.kernel.org/stable/c/ffdde7bf5a439aaa1955ebd581f5c64ab1533963"
        }
      ],
      "title": "net/sched: Abort __tc_modify_qdisc if parent class does not exist",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-38457",
    "datePublished": "2025-07-25T15:27:36.226Z",
    "dateReserved": "2025-04-16T04:51:24.019Z",
    "dateUpdated": "2025-07-28T04:22:51.557Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-38457\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-07-25T16:15:31.403\",\"lastModified\":\"2025-07-29T14:14:55.157\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nnet/sched: Abort __tc_modify_qdisc if parent class does not exist\\n\\nLion\u0027s patch [1] revealed an ancient bug in the qdisc API.\\nWhenever a user creates/modifies a qdisc specifying as a parent another\\nqdisc, the qdisc API will, during grafting, detect that the user is\\nnot trying to attach to a class and reject. However grafting is\\nperformed after qdisc_create (and thus the qdiscs\u0027 init callback) is\\nexecuted. In qdiscs that eventually call qdisc_tree_reduce_backlog\\nduring init or change (such as fq, hhf, choke, etc), an issue\\narises. For example, executing the following commands:\\n\\nsudo tc qdisc add dev lo root handle a: htb default 2\\nsudo tc qdisc add dev lo parent a: handle beef fq\\n\\nQdiscs such as fq, hhf, choke, etc unconditionally invoke\\nqdisc_tree_reduce_backlog() in their control path init() or change() which\\nthen causes a failure to find the child class; however, that does not stop\\nthe unconditional invocation of the assumed child qdisc\u0027s qlen_notify with\\na null class. All these qdiscs make the assumption that class is non-null.\\n\\nThe solution is ensure that qdisc_leaf() which looks up the parent\\nclass, and is invoked prior to qdisc_create(), should return failure on\\nnot finding the class.\\nIn this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the\\nparentid doesn\u0027t correspond to a class, so that we can detect it\\nearlier on and abort before qdisc_create is called.\\n\\n[1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/sched: Abort __tc_modify_qdisc si la clase padre no existe. El parche de Lion [1] revel\u00f3 un error antiguo en la API de qdisc. Siempre que un usuario crea o modifica una qdisc que especifica otra qdisc como padre, la API de qdisc detecta, durante el injerto, que el usuario no intenta asociarse a una clase y lo rechaza. Sin embargo, el injerto se realiza despu\u00e9s de ejecutar qdisc_create (y, por lo tanto, la devoluci\u00f3n de llamada de inicio de la qdisc). En las qdisc que eventualmente llaman a qdisc_tree_reduce_backlog durante la inicializaci\u00f3n o el cambio (como fq, hhf, choke, etc.), surge un problema. Por ejemplo, al ejecutar los siguientes comandos: sudo tc qdisc add dev lo root handle a: htb default 2 sudo tc qdisc add dev lo parent a: handle beef fq Las Qdisc como fq, hhf, choke, etc., invocan incondicionalmente qdisc_tree_reduce_backlog() en su ruta de control init() o change(), lo que provoca un error al no encontrar la clase hija; sin embargo, esto no detiene la invocaci\u00f3n incondicional de qlen_notify de la qdisc hija asumida con una clase nula. Todas estas qdisc asumen que la clase no es nula. La soluci\u00f3n es garantizar que qdisc_leaf(), que busca la clase padre y se invoca antes que qdisc_create(), devuelva un error al no encontrar la clase. En este parche, aprovechamos qdisc_leaf para devolver ERR_PTR siempre que el parentid no corresponda a una clase, de modo que podamos detectarlo antes y abortar antes de que se llame a qdisc_create. [1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/23c165dde88eac405eebb59051ea1fe139a45803\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/25452638f133ac19d75af3f928327d8016952c8e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/4c691d1b6b6dbd73f30ed9ee7da05f037b0c49af\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8ecd651ef24ab50123692a4e3e25db93cb11602a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/90436e72c9622c2f70389070088325a3232d339f\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/923a276c74e25073ae391e930792ac86a9f77f1e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/e28a383d6485c3bb51dc5953552f76c4dea33eea\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ffdde7bf5a439aaa1955ebd581f5c64ab1533963\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Sightings

Author Source Type Date

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
  • Patched: This vulnerability was successfully patched by the user reporting the sighting.
  • Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
  • Not confirmed: The user expresses doubt about the veracity of the vulnerability.
  • Not patched: This vulnerability was not successfully patched by the user reporting the sighting.