CVE-2025-37953 (GCVE-0-2025-37953)
Vulnerability from cvelistv5
Published
2025-05-20 16:01
Modified
2025-08-28 14:42
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: sch_htb: make htb_deactivate() idempotent Alan reported a NULL pointer dereference in htb_next_rb_node() after we made htb_qlen_notify() idempotent. It turns out in the following case it introduced some regression: htb_dequeue_tree(): |-> fq_codel_dequeue() |-> qdisc_tree_reduce_backlog() |-> htb_qlen_notify() |-> htb_deactivate() |-> htb_next_rb_node() |-> htb_deactivate() For htb_next_rb_node(), after calling the 1st htb_deactivate(), the clprio[prio]->ptr could be already set to NULL, which means htb_next_rb_node() is vulnerable here. For htb_deactivate(), although we checked qlen before calling it, in case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again which triggers the warning inside. To fix the issues here, we need to: 1) Make htb_deactivate() idempotent, that is, simply return if we already call it before. 2) Make htb_next_rb_node() safe against ptr==NULL. Many thanks to Alan for testing and for the reproducer.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61d
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0
Impacted products
Vendor Product Version
Linux Linux Version: e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1
Version: 32ae12ce6a9f6bace186ca7335220ff59b6cc3cd
Version: 967955c9e57f8eebfccc298037d4aaf3d42bc1c9
Version: 73cf6af13153d62f9b76eff422eea79dbc70f15e
Version: bbbf5e0f87078b715e7a665d662a2c0e77f044ae
Version: 0a188c0e197383683fd093ab1ea6ce9a5869a6ea
Version: a61f1b5921761fbaf166231418bc1db301e5bf59
Version: 5ba8b837b522d7051ef81bacf3d95383ff8edce5
 Create a notification for this product.
   Linux Linux Version: 6.1.138   ≤
Version: 6.6.90   ≤
Version: 6.12.28   ≤
Version: 6.14.6   ≤
Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_htb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "99ff8a20fd61315bf9ae627440a5ff07d22ee153",
              "status": "affected",
              "version": "e6b45f4de763b00dc1c55e685e2dd1aaf525d3c1",
              "versionType": "git"
            },
            {
              "lessThan": "a9945f7cf1709adc5d2d31cb6cfc85627ce299a8",
              "status": "affected",
              "version": "32ae12ce6a9f6bace186ca7335220ff59b6cc3cd",
              "versionType": "git"
            },
            {
              "lessThan": "c2d25fddd867ce20a266806634eeeb5c30cb520c",
              "status": "affected",
              "version": "967955c9e57f8eebfccc298037d4aaf3d42bc1c9",
              "versionType": "git"
            },
            {
              "lessThan": "c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0",
              "status": "affected",
              "version": "73cf6af13153d62f9b76eff422eea79dbc70f15e",
              "versionType": "git"
            },
            {
              "lessThan": "31ff70ad39485698cf779f2078132d80b57f6c07",
              "status": "affected",
              "version": "bbbf5e0f87078b715e7a665d662a2c0e77f044ae",
              "versionType": "git"
            },
            {
              "lessThan": "98cd7ed92753090a714f0802d4434314526fe61d",
              "status": "affected",
              "version": "0a188c0e197383683fd093ab1ea6ce9a5869a6ea",
              "versionType": "git"
            },
            {
              "lessThan": "c4792b9e38d2f61b07eac72f10909fa76130314b",
              "status": "affected",
              "version": "a61f1b5921761fbaf166231418bc1db301e5bf59",
              "versionType": "git"
            },
            {
              "lessThan": "3769478610135e82b262640252d90f6efb05be71",
              "status": "affected",
              "version": "5ba8b837b522d7051ef81bacf3d95383ff8edce5",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_htb.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6.1.139",
              "status": "affected",
              "version": "6.1.138",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.91",
              "status": "affected",
              "version": "6.6.90",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.29",
              "status": "affected",
              "version": "6.12.28",
              "versionType": "semver"
            },
            {
              "lessThan": "6.14.7",
              "status": "affected",
              "version": "6.14.6",
              "versionType": "semver"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.139",
                  "versionStartIncluding": "6.1.138",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.91",
                  "versionStartIncluding": "6.6.90",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.29",
                  "versionStartIncluding": "6.12.28",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14.7",
                  "versionStartIncluding": "6.14.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsch_htb: make htb_deactivate() idempotent\n\nAlan reported a NULL pointer dereference in htb_next_rb_node()\nafter we made htb_qlen_notify() idempotent.\n\nIt turns out in the following case it introduced some regression:\n\nhtb_dequeue_tree():\n  |-\u003e fq_codel_dequeue()\n    |-\u003e qdisc_tree_reduce_backlog()\n      |-\u003e htb_qlen_notify()\n        |-\u003e htb_deactivate()\n  |-\u003e htb_next_rb_node()\n  |-\u003e htb_deactivate()\n\nFor htb_next_rb_node(), after calling the 1st htb_deactivate(), the\nclprio[prio]-\u003eptr could be already set to  NULL, which means\nhtb_next_rb_node() is vulnerable here.\n\nFor htb_deactivate(), although we checked qlen before calling it, in\ncase of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again\nwhich triggers the warning inside.\n\nTo fix the issues here, we need to:\n\n1) Make htb_deactivate() idempotent, that is, simply return if we\n   already call it before.\n2) Make htb_next_rb_node() safe against ptr==NULL.\n\nMany thanks to Alan for testing and for the reproducer."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-08-28T14:42:55.095Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153"
        },
        {
          "url": "https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8"
        },
        {
          "url": "https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520c"
        },
        {
          "url": "https://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0"
        },
        {
          "url": "https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07"
        },
        {
          "url": "https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61d"
        },
        {
          "url": "https://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314b"
        },
        {
          "url": "https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71"
        }
      ],
      "title": "sch_htb: make htb_deactivate() idempotent",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37953",
    "datePublished": "2025-05-20T16:01:47.818Z",
    "dateReserved": "2025-04-16T04:51:23.973Z",
    "dateUpdated": "2025-08-28T14:42:55.095Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2025-37953\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-05-20T16:15:33.483\",\"lastModified\":\"2025-08-28T15:15:47.660\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nsch_htb: make htb_deactivate() idempotent\\n\\nAlan reported a NULL pointer dereference in htb_next_rb_node()\\nafter we made htb_qlen_notify() idempotent.\\n\\nIt turns out in the following case it introduced some regression:\\n\\nhtb_dequeue_tree():\\n  |-\u003e fq_codel_dequeue()\\n    |-\u003e qdisc_tree_reduce_backlog()\\n      |-\u003e htb_qlen_notify()\\n        |-\u003e htb_deactivate()\\n  |-\u003e htb_next_rb_node()\\n  |-\u003e htb_deactivate()\\n\\nFor htb_next_rb_node(), after calling the 1st htb_deactivate(), the\\nclprio[prio]-\u003eptr could be already set to  NULL, which means\\nhtb_next_rb_node() is vulnerable here.\\n\\nFor htb_deactivate(), although we checked qlen before calling it, in\\ncase of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again\\nwhich triggers the warning inside.\\n\\nTo fix the issues here, we need to:\\n\\n1) Make htb_deactivate() idempotent, that is, simply return if we\\n   already call it before.\\n2) Make htb_next_rb_node() safe against ptr==NULL.\\n\\nMany thanks to Alan for testing and for the reproducer.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: sch_htb: hacer que htb_deactivate() sea idempotente. Alan inform\u00f3 una desreferencia de puntero NULL en htb_next_rb_node() despu\u00e9s de que htb_qlen_notify() fuera idempotente. Resulta que en el siguiente caso introdujo alguna regresi\u00f3n: htb_dequeue_tree(): |-\u0026gt; fq_codel_dequeue() |-\u0026gt; qdisc_tree_reduce_backlog() |-\u0026gt; htb_qlen_notify() |-\u0026gt; htb_deactivate() |-\u0026gt; htb_next_rb_node() |-\u0026gt; htb_deactivate() Para htb_next_rb_node(), despu\u00e9s de llamar al primer htb_deactivate(), el clprio[prio]-\u0026gt;ptr podr\u00eda estar ya establecido en NULL, lo que significa que htb_next_rb_node() es vulnerable aqu\u00ed. Para htb_deactivate(), aunque verificamos qlen antes de llamarlo, en caso de qlen==0 despu\u00e9s de qdisc_tree_reduce_backlog(), podemos llamarlo nuevamente, lo que activa la advertencia interna. Para solucionar estos problemas, necesitamos: 1) Hacer que htb_deactivate() sea idempotente, es decir, que simplemente regrese si ya lo llamamos. 2) Hacer que htb_next_rb_node() sea seguro contra ptr==NULL. Muchas gracias a Alan por las pruebas y por el reproductor.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/31ff70ad39485698cf779f2078132d80b57f6c07\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3769478610135e82b262640252d90f6efb05be71\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/98cd7ed92753090a714f0802d4434314526fe61d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/99ff8a20fd61315bf9ae627440a5ff07d22ee153\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a9945f7cf1709adc5d2d31cb6cfc85627ce299a8\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c2d25fddd867ce20a266806634eeeb5c30cb520c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c4792b9e38d2f61b07eac72f10909fa76130314b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c928dd4f6bf0c25c72b11824a1e9ac9bd37296a0\",\"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.