Vulnerability-Lookup

FKIE_CVE-2026-74267

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-10-16 19:17

Severity

9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen Whenever codel drops packets during peek, it calls qdisc_tree_reduce_backlog. An issue arises because it calls qdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops to zero, but peek returns an skb, the parent's qlen_notify callback will be executed even though codel still has 1 packet on the queue and, thus, will mistakenly deactivate the parent's class causing issues like a wild memory access when qfq has codel as a child: [ 36.339843][ T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI [ 36.340408][ T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] [ 36.340737][ T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full) [ 36.341113][ T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 36.341357][ T370] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq [ 36.342221][ T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216 [ 36.342422][ T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000 [ 36.342664][ T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000 [ 36.342905][ T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024 [ 36.343140][ T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000 [ 36.343383][ T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578 [ 36.343631][ T370] FS: 00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000 [ 36.343911][ T370] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 36.344116][ T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0 [ 36.344359][ T370] PKRU: 55555554 [ 36.344481][ T370] Call Trace: ... [ 36.345054][ T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq [ 36.345222][ T370] qdisc_reset (net/sched/sch_generic.c:1057) [ 36.345503][ T370] __qdisc_destroy (net/sched/sch_generic.c:1096) [ 36.345677][ T370] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159) [ 36.346335][ T370] tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556) Fix this by only calling qdisc_tree_reduce_backlog in peek after the qlen is restored.

References

	URL	Tags
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/755108bb7a5083e911294c416cfea605dc75632f
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/7a05af7f58566682b73578b72ca8e53a268c43bd
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/91e0a793a72374c20ab31a40ccec21373e82e973
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bb9cfd874ee884117b33e92a002b9a45b48202f4
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e4615aa6bb7802944ae790cb4b3ef8c1b7491af3
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/e8c6dbadf139cb14ea6ed14add6ed6e88504dedd
	416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/eba49fd85995a3851c597fa2d214f8d21736e1d8

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bb9cfd874ee884117b33e92a002b9a45b48202f4",
              "status": "affected",
              "version": "cc71a757da78dd4aa1b4a9b19cb011833730ccf2",
              "versionType": "git"
            },
            {
              "lessThan": "7a05af7f58566682b73578b72ca8e53a268c43bd",
              "status": "affected",
              "version": "eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450",
              "versionType": "git"
            },
            {
              "lessThan": "eba49fd85995a3851c597fa2d214f8d21736e1d8",
              "status": "affected",
              "version": "829c49b6b2ff45b043739168fd1245e4e1a91a30",
              "versionType": "git"
            },
            {
              "lessThan": "e8c6dbadf139cb14ea6ed14add6ed6e88504dedd",
              "status": "affected",
              "version": "2f9761a94bae33d26e6a81b31b36e7d776d93dc1",
              "versionType": "git"
            },
            {
              "lessThan": "e4615aa6bb7802944ae790cb4b3ef8c1b7491af3",
              "status": "affected",
              "version": "4d55144b12e742404bb3f8fee6038bafbf45619d",
              "versionType": "git"
            },
            {
              "lessThan": "755108bb7a5083e911294c416cfea605dc75632f",
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "versionType": "git"
            },
            {
              "lessThan": "91e0a793a72374c20ab31a40ccec21373e82e973",
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "versionType": "git"
            },
            {
              "lessThan": "52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3",
              "status": "affected",
              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7a742a9506849d1c1aa71e36c89855ceddc7d58e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e73c838c80dccb9e4f19becc11d9f3cb4a27d483",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.261",
              "status": "affected",
              "version": "5.10.241",
              "versionType": "semver"
            },
            {
              "lessThan": "5.15.212",
              "status": "affected",
              "version": "5.15.190",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.135",
              "versionType": "semver"
            },
            {
              "lessThan": "6.6.145",
              "status": "affected",
              "version": "6.6.88",
              "versionType": "semver"
            },
            {
              "lessThan": "6.12.97",
              "status": "affected",
              "version": "6.12.24",
              "versionType": "semver"
            },
            {
              "lessThan": "5.5",
              "status": "affected",
              "version": "5.4.297",
              "versionType": "semver"
            },
            {
              "lessThan": "6.14",
              "status": "affected",
              "version": "6.13.12",
              "versionType": "semver"
            },
            {
              "lessThan": "6.15",
              "status": "affected",
              "version": "6.14.3",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.15"
            },
            {
              "lessThan": "6.15",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nnet/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever codel drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent\u0027s qlen_notify callback will\nbe executed even though codel still has 1 packet on the queue and, thus,\nwill mistakenly deactivate the parent\u0027s class causing issues like a wild\nmemory access when qfq has codel as a child:\n\n[   36.339843][  T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI\n[   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]\n[   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full)\n[   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[   36.341357][  T370] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq\n[   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216\n[   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000\n[   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000\n[   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024\n[   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000\n[   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578\n[   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000\n[   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0\n[   36.344359][  T370] PKRU: 55555554\n[   36.344481][  T370] Call Trace:\n...\n[   36.345054][  T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq\n[   36.345222][  T370]  qdisc_reset (net/sched/sch_generic.c:1057)\n[   36.345503][  T370]  __qdisc_destroy (net/sched/sch_generic.c:1096)\n[   36.345677][  T370]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)\n[   36.346335][  T370]  tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored."
    }
  ],
  "id": "CVE-2026-74267",
  "lastModified": "2026-10-16T19:17:35.090",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 9.8,
          "baseSeverity": "CRITICAL",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-74267",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-16T18:51:44.190573Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-08-15T06:22:26.030",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/755108bb7a5083e911294c416cfea605dc75632f"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/7a05af7f58566682b73578b72ca8e53a268c43bd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/91e0a793a72374c20ab31a40ccec21373e82e973"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bb9cfd874ee884117b33e92a002b9a45b48202f4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e4615aa6bb7802944ae790cb4b3ef8c1b7491af3"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/e8c6dbadf139cb14ea6ed14add6ed6e88504dedd"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/eba49fd85995a3851c597fa2d214f8d21736e1d8"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}

CVE-2026-74267 (GCVE-0-2026-74267)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:57 – Updated: 2026-10-16 18:55

Title

net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen

Summary

Severity

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: yes Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-16 18:51 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6992 records in the last 180 days details

References

8 references

URL	Tags
https://git.kernel.org/stable/c/bb9cfd874ee884117…
https://git.kernel.org/stable/c/7a05af7f58566682b…
https://git.kernel.org/stable/c/eba49fd85995a3851…
https://git.kernel.org/stable/c/e8c6dbadf139cb14e…
https://git.kernel.org/stable/c/e4615aa6bb7802944…
https://git.kernel.org/stable/c/755108bb7a5083e91…
https://git.kernel.org/stable/c/91e0a793a72374c20…
https://git.kernel.org/stable/c/52f1da34c9f4d5bdc…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: cc71a757da78dd4aa1b4a9b19cb011833730ccf2 , < bb9cfd874ee884117b33e92a002b9a45b48202f4 (git) Affected: eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450 , < 7a05af7f58566682b73578b72ca8e53a268c43bd (git) Affected: 829c49b6b2ff45b043739168fd1245e4e1a91a30 , < eba49fd85995a3851c597fa2d214f8d21736e1d8 (git) Affected: 2f9761a94bae33d26e6a81b31b36e7d776d93dc1 , < e8c6dbadf139cb14ea6ed14add6ed6e88504dedd (git) Affected: 4d55144b12e742404bb3f8fee6038bafbf45619d , < e4615aa6bb7802944ae790cb4b3ef8c1b7491af3 (git) Affected: 342debc12183b51773b3345ba267e9263bdfaaef , < 755108bb7a5083e911294c416cfea605dc75632f (git) Affected: 342debc12183b51773b3345ba267e9263bdfaaef , < 91e0a793a72374c20ab31a40ccec21373e82e973 (git) Affected: 342debc12183b51773b3345ba267e9263bdfaaef , < 52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3 (git) Affected: 7a742a9506849d1c1aa71e36c89855ceddc7d58e (git) Affected: e73c838c80dccb9e4f19becc11d9f3cb4a27d483 (git) Affected: a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31 (git) Affected: 5.10.241 , < 5.10.261 (semver) Affected: 5.15.190 , < 5.15.212 (semver) Affected: 6.1.135 , < 6.1.178 (semver) Affected: 6.6.88 , < 6.6.145 (semver) Affected: 6.12.24 , < 6.12.97 (semver) Affected: 5.4.297 , < 5.5 (semver) Affected: 6.13.12 , < 6.14 (semver) Affected: 6.14.3 , < 6.15 (semver)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (semver) Unaffected: 5.10.261 , ≤ 5.10.* (semver) Unaffected: 5.15.212 , ≤ 5.15.* (semver) Unaffected: 6.1.178 , ≤ 6.1.* (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.97 , ≤ 6.12.* (semver) Unaffected: 6.18.40 , ≤ 6.18.* (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-74267",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-16T18:51:44.190573Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-10-16T18:55:28.845Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bb9cfd874ee884117b33e92a002b9a45b48202f4",
              "status": "affected",
              "version": "cc71a757da78dd4aa1b4a9b19cb011833730ccf2",
              "versionType": "git"
            },
            {
              "lessThan": "7a05af7f58566682b73578b72ca8e53a268c43bd",
              "status": "affected",
              "version": "eda741fe155ddf5ecd2dd3bfbd4fc3c0c7dbb450",
              "versionType": "git"
            },
            {
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              "versionType": "git"
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              "version": "342debc12183b51773b3345ba267e9263bdfaaef",
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            {
              "status": "affected",
              "version": "e73c838c80dccb9e4f19becc11d9f3cb4a27d483",
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            {
              "status": "affected",
              "version": "a57fe60ef4cf96bfbb6b58397ec28bdb5a5c6b31",
              "versionType": "git"
            },
            {
              "lessThan": "5.10.261",
              "status": "affected",
              "version": "5.10.241",
              "versionType": "semver"
            },
            {
              "lessThan": "5.15.212",
              "status": "affected",
              "version": "5.15.190",
              "versionType": "semver"
            },
            {
              "lessThan": "6.1.178",
              "status": "affected",
              "version": "6.1.135",
              "versionType": "semver"
            },
            {
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              "status": "affected",
              "version": "6.6.88",
              "versionType": "semver"
            },
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              "status": "affected",
              "version": "6.12.24",
              "versionType": "semver"
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            {
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              "status": "affected",
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              "lessThan": "6.14",
              "status": "affected",
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              "versionType": "semver"
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            {
              "lessThan": "6.15",
              "status": "affected",
              "version": "6.14.3",
              "versionType": "semver"
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/sch_codel.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "6.15"
            },
            {
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              "version": "0",
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            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.261",
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                {
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                {
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              ],
              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen\n\nWhenever codel drops packets during peek, it calls\nqdisc_tree_reduce_backlog. An issue arises because it calls\nqdisc_tree_reduce_backlog before it reincrements the qlen. If qlen drops\nto zero, but peek returns an skb, the parent\u0027s qlen_notify callback will\nbe executed even though codel still has 1 packet on the queue and, thus,\nwill mistakenly deactivate the parent\u0027s class causing issues like a wild\nmemory access when qfq has codel as a child:\n\n[   36.339843][  T370] Oops: general protection fault, probably for non-canonical address 0xfbd59c0000000024: 0000 [#1] SMP KASAN NOPTI\n[   36.340408][  T370] KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127]\n[   36.340737][  T370] CPU: 2 UID: 0 PID: 370 Comm: tc Not tainted 7.1.0-rc5-00287-g66e13b626592 #87 PREEMPT(full)\n[   36.341113][  T370] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011\n[   36.341357][  T370] RIP: 0010:qfq_deactivate_agg (include/linux/list.h:1029 (discriminator 2) include/linux/list.h:1043 (discriminator 2) net/sched/sch_qfq.c:1369 (discriminator 2) net/sched/sch_qfq.c:1395 (discriminator 2)) sch_qfq\n[   36.342221][  T370] RSP: 0018:ffff8881100ef370 EFLAGS: 00010216\n[   36.342422][  T370] RAX: 0000000000000000 RBX: ffff8881058a9568 RCX: dffffc0000000000\n[   36.342664][  T370] RDX: 1ffff11021064dc3 RSI: ffff888108326e00 RDI: dffffc0000000000\n[   36.342905][  T370] RBP: ffff8881058a8280 R08: dead000000000122 R09: 1bd5a00000000024\n[   36.343140][  T370] R10: fffffbfff2940329 R11: fffffbfff2940329 R12: 0000000000000000\n[   36.343383][  T370] R13: dead000000000100 R14: ffff8881058a9580 R15: ffff8881058a9578\n[   36.343631][  T370] FS:  00007fc04b0ca780(0000) GS:ffff888184fef000(0000) knlGS:0000000000000000\n[   36.343911][  T370] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   36.344116][  T370] CR2: 0000557c02c02000 CR3: 000000010e0ba000 CR4: 0000000000750ef0\n[   36.344359][  T370] PKRU: 55555554\n[   36.344481][  T370] Call Trace:\n...\n[   36.345054][  T370] qfq_reset_qdisc (net/sched/sch_qfq.c:357 net/sched/sch_qfq.c:1487) sch_qfq\n[   36.345222][  T370]  qdisc_reset (net/sched/sch_generic.c:1057)\n[   36.345503][  T370]  __qdisc_destroy (net/sched/sch_generic.c:1096)\n[   36.345677][  T370]  qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159)\n[   36.346335][  T370]  tc_get_qdisc (net/sched/sch_api.c:1528 net/sched/sch_api.c:1556)\n\nFix this by only calling qdisc_tree_reduce_backlog in peek after the\nqlen is restored."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - Remote senders reach the bug when packets traverse a QFQ (or other qlen_notify parent) with a codel child: qfq_enqueue() and qfq_dequeue() call the child peek handler during __dev_queue_xmit scheduling, and CoDel can drop there before qlen is restored.\nAC:L - The attacker controls traffic rate, packet size, and CoDel drop behavior to force drops during peek while qlen reads zero; this is a deterministic logic bug, not a race on uncontrollable kernel state or a rare compile-time configuration.\nPR:N - On systems where an operator has already deployed a parent qdisc with a codel child, any remote party that can send packets into the shaped class can trigger the faulty peek/drop path with no account or capabilities on the victim host.\nUI:N - Exploitation requires only attacker-generated traffic (and, for full crash during teardown, attacker-initiated tc reconfiguration); no independent action by another user or administrator is needed at trigger time.\nS:U - The flaw corrupts in-kernel QFQ/CoDel scheduler structures and memory within the same kernel security domain; it does not cross VM, container, or IOMMU authority boundaries.\nC:H - False qlen_notify prematurely deactivates QFQ aggregates while packets remain; the fix commit shows KASAN wild-memory-access on poisoned aggregate list nodes in qfq_deactivate_agg(), giving attacker-influenced reads from freed/corrupted scheduler memory.\nI:H - Corrupted aggregate/class linkage leads to invalid hlist operations and inconsistent scheduler state that can be steered with heap layout control, yielding memory corruption primitives usable for arbitrary kernel writes or control-flow hijack.\nA:H - The published oops is a general protection fault from corrupted QFQ state during qdisc teardown, and the same corruption during live packet scheduling can reliably kernel-panic or hang affected hosts."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:45:13.330Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bb9cfd874ee884117b33e92a002b9a45b48202f4"
        },
        {
          "url": "https://git.kernel.org/stable/c/7a05af7f58566682b73578b72ca8e53a268c43bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/eba49fd85995a3851c597fa2d214f8d21736e1d8"
        },
        {
          "url": "https://git.kernel.org/stable/c/e8c6dbadf139cb14ea6ed14add6ed6e88504dedd"
        },
        {
          "url": "https://git.kernel.org/stable/c/e4615aa6bb7802944ae790cb4b3ef8c1b7491af3"
        },
        {
          "url": "https://git.kernel.org/stable/c/755108bb7a5083e911294c416cfea605dc75632f"
        },
        {
          "url": "https://git.kernel.org/stable/c/91e0a793a72374c20ab31a40ccec21373e82e973"
        },
        {
          "url": "https://git.kernel.org/stable/c/52f1da34c9f4d5bdc1e8b44242da5c7ba8db85f3"
        }
      ],
      "title": "net/sched: sch_codel: Do not call qdisc_tree_reduce_backlog during peek before restoring qlen",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74267",
    "datePublished": "2026-08-15T05:57:42.263Z",
    "dateReserved": "2026-08-15T05:44:03.878Z",
    "dateUpdated": "2026-10-16T18:55:28.845Z",
    "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.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

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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.
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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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