CVE-2025-37797 (GCVE-0-2025-37797)

Vulnerability from cvelistv5 – Published: 2025-05-02 14:16 – Updated: 2025-11-03 19:55
VLAI?
Title
net_sched: hfsc: Fix a UAF vulnerability in class handling
Summary
In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 28b09a067831f7317c3841812276022d6c940677 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 39b9095dd3b55d9b2743df038c32138efa34a9de (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < fcc8ede663569c704fb00a702973bd6c00373283 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 20d584a33e480ae80d105f43e0e7b56784da41b9 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 3aa852e3605000d5c47035c3fc3a986d14ccfa9f (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 86cd4641c713455a4f1c8e54c370c598c2b1cee0 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < bb583c88d23b72d8d16453d24856c99bd93dadf5 (git)
Affected: 21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14 , < 3df275ef0a6ae181e8428a6589ef5d5231e58b5c (git)
Create a notification for this product.
    Linux Linux Affected: 4.14
Unaffected: 0 , < 4.14 (semver)
Unaffected: 5.4.293 , ≤ 5.4.* (semver)
Unaffected: 5.10.237 , ≤ 5.10.* (semver)
Unaffected: 5.15.181 , ≤ 5.15.* (semver)
Unaffected: 6.1.136 , ≤ 6.1.* (semver)
Unaffected: 6.6.89 , ≤ 6.6.* (semver)
Unaffected: 6.12.26 , ≤ 6.12.* (semver)
Unaffected: 6.14.5 , ≤ 6.14.* (semver)
Unaffected: 6.15 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2025-11-03T19:55:28.428Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html"
          },
          {
            "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_hfsc.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "28b09a067831f7317c3841812276022d6c940677",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "39b9095dd3b55d9b2743df038c32138efa34a9de",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "fcc8ede663569c704fb00a702973bd6c00373283",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "20d584a33e480ae80d105f43e0e7b56784da41b9",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "3aa852e3605000d5c47035c3fc3a986d14ccfa9f",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "86cd4641c713455a4f1c8e54c370c598c2b1cee0",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "bb583c88d23b72d8d16453d24856c99bd93dadf5",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            },
            {
              "lessThan": "3df275ef0a6ae181e8428a6589ef5d5231e58b5c",
              "status": "affected",
              "version": "21f4d5cc25ec0e6e8eb8420dd2c399e6d2fc7d14",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_hfsc.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": "5.4.*",
              "status": "unaffected",
              "version": "5.4.293",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.237",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.181",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.136",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.89",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.26",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.14.*",
              "status": "unaffected",
              "version": "6.14.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "6.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.293",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.237",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.181",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.136",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.89",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.26",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.14.5",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.15",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet_sched: hfsc: Fix a UAF vulnerability in class handling\n\nThis patch fixes a Use-After-Free vulnerability in the HFSC qdisc class\nhandling. The issue occurs due to a time-of-check/time-of-use condition\nin hfsc_change_class() when working with certain child qdiscs like netem\nor codel.\n\nThe vulnerability works as follows:\n1. hfsc_change_class() checks if a class has packets (q.qlen != 0)\n2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g.,\n   codel, netem) might drop packets and empty the queue\n3. The code continues assuming the queue is still non-empty, adding\n   the class to vttree\n4. This breaks HFSC scheduler assumptions that only non-empty classes\n   are in vttree\n5. Later, when the class is destroyed, this can lead to a Use-After-Free\n\nThe fix adds a second queue length check after qdisc_peek_len() to verify\nthe queue wasn\u0027t emptied."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2025-05-26T05:21:05.138Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/28b09a067831f7317c3841812276022d6c940677"
        },
        {
          "url": "https://git.kernel.org/stable/c/39b9095dd3b55d9b2743df038c32138efa34a9de"
        },
        {
          "url": "https://git.kernel.org/stable/c/fcc8ede663569c704fb00a702973bd6c00373283"
        },
        {
          "url": "https://git.kernel.org/stable/c/20d584a33e480ae80d105f43e0e7b56784da41b9"
        },
        {
          "url": "https://git.kernel.org/stable/c/3aa852e3605000d5c47035c3fc3a986d14ccfa9f"
        },
        {
          "url": "https://git.kernel.org/stable/c/86cd4641c713455a4f1c8e54c370c598c2b1cee0"
        },
        {
          "url": "https://git.kernel.org/stable/c/bb583c88d23b72d8d16453d24856c99bd93dadf5"
        },
        {
          "url": "https://git.kernel.org/stable/c/3df275ef0a6ae181e8428a6589ef5d5231e58b5c"
        }
      ],
      "title": "net_sched: hfsc: Fix a UAF vulnerability in class handling",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2025-37797",
    "datePublished": "2025-05-02T14:16:01.905Z",
    "dateReserved": "2025-04-16T04:51:23.941Z",
    "dateUpdated": "2025-11-03T19:55:28.428Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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 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.