CVE-2026-46154 (GCVE-0-2026-46154)
Vulnerability from cvelistv5
Published
2026-05-28 09:36
Modified
2026-08-05 12:30
Severity ?
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Read scx_root under scx_cgroup_ops_rwsem in cgroup setters scx_group_set_{weight,idle,bandwidth}() cache scx_root before acquiring scx_cgroup_ops_rwsem, so the pointer can be stale by the time the op runs. If the loaded scheduler is disabled and freed (via RCU work) and another is enabled between the naked load and the rwsem acquire, the reader sees scx_cgroup_enabled=true (the new scheduler's) but dereferences the freed one - UAF on SCX_HAS_OP(sch, ...) / SCX_CALL_OP(sch, ...). scx_cgroup_enabled is toggled only under scx_cgroup_ops_rwsem write (scx_cgroup_{init,exit}), so reading scx_root inside the rwsem read section correlates @sch with the enabled snapshot.
References
Impacted products
Vendor Product Version
Linux Linux Version: a5bd6ba30b3364354269b81ac55c2edca9a96d6d
Version: a5bd6ba30b3364354269b81ac55c2edca9a96d6d
Version: a5bd6ba30b3364354269b81ac55c2edca9a96d6d
 Create a notification for this product.
Show details on NVD website

To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "ce9aaa3af445c391735c9d000c4db60dfd5640d4",
              "status": "affected",
              "version": "a5bd6ba30b3364354269b81ac55c2edca9a96d6d",
              "versionType": "git"
            },
            {
              "lessThan": "0f54f6355575971673d8aac7da107ec4178e45bd",
              "status": "affected",
              "version": "a5bd6ba30b3364354269b81ac55c2edca9a96d6d",
              "versionType": "git"
            },
            {
              "lessThan": "80afd4c84bc8f5e80145ce35279f5ce53f6043db",
              "status": "affected",
              "version": "a5bd6ba30b3364354269b81ac55c2edca9a96d6d",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.18"
            },
            {
              "lessThan": "6.18",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.32",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.32",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.7",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsched_ext: Read scx_root under scx_cgroup_ops_rwsem in cgroup setters\n\nscx_group_set_{weight,idle,bandwidth}() cache scx_root before acquiring\nscx_cgroup_ops_rwsem, so the pointer can be stale by the time the op runs.\nIf the loaded scheduler is disabled and freed (via RCU work) and another is\nenabled between the naked load and the rwsem acquire, the reader sees\nscx_cgroup_enabled=true (the new scheduler\u0027s) but dereferences the freed one\n- UAF on SCX_HAS_OP(sch, ...) / SCX_CALL_OP(sch, ...).\n\nscx_cgroup_enabled is toggled only under scx_cgroup_ops_rwsem write\n(scx_cgroup_{init,exit}), so reading scx_root inside the rwsem read section\ncorrelates @sch with the enabled snapshot."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerable setters are reached only by writing cgroup CPU control files (cpu.weight/idle/max) via the local filesystem/syscall interface; there is no network-reachable path.\nAC:H - The UAF requires a full scheduler disable\u2192RCU-free\u2192enable cycle to land within the window after the naked scx_root load; the unprivileged attacker reliably controls only the cgroup-write side, not the privileged scheduler-swap timing, so success cannot be achieved at will.\nPR:L - cpu.weight/cpu.idle/cpu.max are delegatable in cgroup v2, so an unprivileged user in a delegated subtree (common in container/systemd setups) can repeatedly invoke the setters that perform the stale dereference.\nUI:N - Triggering the setter requires only programmatic writes to cgroup files; no victim interaction is involved.\nS:U - The freed object and the corrupted control flow are both within the kernel\u0027s own security authority; no VM/IOMMU/sandbox boundary is crossed.\nC:H - The UAF reads the freed scx_sched (has_op bitmap and ops pointers); a reallocated, attacker-shaped object enables disclosure of freed/controlled kernel memory.\nI:H - The bug culminates in an indirect call through sch-\u003eops.cgroup_*() on freed memory; heap-spraying the freed scx_sched yields a control-flow-hijack/arbitrary-write primitive.\nA:H - Dereferencing and calling through a freed scx_sched reliably causes an oops/panic, taking down the kernel."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:30:05.703Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/ce9aaa3af445c391735c9d000c4db60dfd5640d4"
        },
        {
          "url": "https://git.kernel.org/stable/c/0f54f6355575971673d8aac7da107ec4178e45bd"
        },
        {
          "url": "https://git.kernel.org/stable/c/80afd4c84bc8f5e80145ce35279f5ce53f6043db"
        }
      ],
      "title": "sched_ext: Read scx_root under scx_cgroup_ops_rwsem in cgroup setters",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46154",
    "datePublished": "2026-05-28T09:36:10.310Z",
    "dateReserved": "2026-05-13T15:03:33.102Z",
    "dateUpdated": "2026-08-05T12:30:05.703Z",
    "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 seen somewhere by the user.
  • Confirmed: The vulnerability is confirmed from an analyst perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • 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.