CVE-2026-74736 (GCVE-0-2026-74736)
Vulnerability from cvelistv5
Published
2026-08-26 14:36
Modified
2026-08-27 05:00
Summary
In the Linux kernel, the following vulnerability has been resolved: net/sched: cls_bpf: reject dev-bound programs bound to a different device cls_bpf_prog_from_efd() obtained a SCHED_CLS program via bpf_prog_get_type_dev() but never verified that a device-bound (offloaded) program's bound netdev matches the TC netdev the classifier is being attached to. This let a program loaded with prog_ifindex for device A be attached via cls_bpf + skip_sw to device B; deleting device A then destroyed the program's offload state while it was still attached to device B, triggering a netdevsim WARN (panic with panic_on_warn=1). Mirror the XDP attach path (net/core/dev.c) and reject the attach with -EINVAL when a dev-bound program's bound device does not match the target device.
Impacted products
Vendor Product Version
Linux Linux Version: 2b3486bc2d237ec345b3942b7be5deabf8c8fed1
Version: 2b3486bc2d237ec345b3942b7be5deabf8c8fed1
Version: 2b3486bc2d237ec345b3942b7be5deabf8c8fed1
Version: 2b3486bc2d237ec345b3942b7be5deabf8c8fed1
Version: 2b3486bc2d237ec345b3942b7be5deabf8c8fed1
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ec5a552f4b2d841c6c021752450716e1a9676661",
              "status": "affected",
              "version": "2b3486bc2d237ec345b3942b7be5deabf8c8fed1",
              "versionType": "git"
            },
            {
              "lessThan": "daf546ab5763ce6a18280cb4db060e836c515301",
              "status": "affected",
              "version": "2b3486bc2d237ec345b3942b7be5deabf8c8fed1",
              "versionType": "git"
            },
            {
              "lessThan": "adb3e7c26a51a10d94a241c6de7a81a2863dcacf",
              "status": "affected",
              "version": "2b3486bc2d237ec345b3942b7be5deabf8c8fed1",
              "versionType": "git"
            },
            {
              "lessThan": "5685bbbd3cbfbeb0de96a1d275a5ca073dfebb5e",
              "status": "affected",
              "version": "2b3486bc2d237ec345b3942b7be5deabf8c8fed1",
              "versionType": "git"
            },
            {
              "lessThan": "120977e2c096deea4e866e4273be9220b957c29e",
              "status": "affected",
              "version": "2b3486bc2d237ec345b3942b7be5deabf8c8fed1",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "net/sched/cls_bpf.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.3"
            },
            {
              "lessThan": "6.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.153",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.105",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.10",
              "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": "6.6.153",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.105",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.46",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.10",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/sched: cls_bpf: reject dev-bound programs bound to a different device\n\ncls_bpf_prog_from_efd() obtained a SCHED_CLS program via\nbpf_prog_get_type_dev() but never verified that a device-bound (offloaded)\nprogram\u0027s bound netdev matches the TC netdev the classifier is being\nattached to. This let a program loaded with prog_ifindex for device A be\nattached via cls_bpf + skip_sw to device B; deleting device A then\ndestroyed the program\u0027s offload state while it was still attached to\ndevice B, triggering a netdevsim WARN (panic with panic_on_warn=1).\n\nMirror the XDP attach path (net/core/dev.c) and reject the attach with\n-EINVAL when a dev-bound program\u0027s bound device does not match the\ntarget device."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local RTM_NEWTFILTER and bpf(2) syscalls to misattach a dev-bound cls_bpf program and delete the bound netdev; received network packets are not the trigger and no remote pre-auth path reaches this code.\nAC:L - The attacker fully controls bpf load on device A, cls_bpf attach with SKIP_SW to device B, and deletion of device A, deterministically reproducing the offload teardown while the program remains referenced on device B.\nPR:L - RTNL TC filter operations require CAP_NET_ADMIN and BPF_PROG_TYPE_SCHED_CLS loading requires CAP_NET_ADMIN (and often CAP_BPF), all grantable to the namespace root created by an unprivileged user via unshare -Urn per kernel CNA guidance.\nUI:N - No victim interaction is required; the attacker performs bpf program load, cls_bpf attach, and netdev deletion through their own namespace-local administrative operations.\nS:U - Impact is kernel memory corruption, panic, or privilege escalation within the same host kernel and does not cross VM, container, or IOMMU boundaries into a separate security authority.\nC:H - Deleting the bound netdev destroys bpf offload private state while cls_bpf on another device still holds the program reference, freeing dev_private metadata and creating a use-after-free that can leak kernel heap contents on subsequent TC/BPF operations.\nI:H - The lifetime mismatch frees attacker-influenceable offload objects while references remain, enabling heap grooming and memory corruption that can be leveraged into arbitrary kernel writes or code execution.\nA:H - netdevsim WARNs when offload state is destroyed while the program remains loaded on another port, causing kernel panic on systems with panic_on_warn enabled, and dereferencing freed offload state can also trigger kernel oops or hang."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-27T05:00:58.564Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ec5a552f4b2d841c6c021752450716e1a9676661"
        },
        {
          "url": "https://git.kernel.org/stable/c/daf546ab5763ce6a18280cb4db060e836c515301"
        },
        {
          "url": "https://git.kernel.org/stable/c/adb3e7c26a51a10d94a241c6de7a81a2863dcacf"
        },
        {
          "url": "https://git.kernel.org/stable/c/5685bbbd3cbfbeb0de96a1d275a5ca073dfebb5e"
        },
        {
          "url": "https://git.kernel.org/stable/c/120977e2c096deea4e866e4273be9220b957c29e"
        }
      ],
      "title": "net/sched: cls_bpf: reject dev-bound programs bound to a different device",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74736",
    "datePublished": "2026-08-26T14:36:49.950Z",
    "dateReserved": "2026-08-15T05:44:03.930Z",
    "dateUpdated": "2026-08-27T05:00:58.564Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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  • Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
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