CVE-2026-31734 (GCVE-0-2026-31734)

Vulnerability from cvelistv5 – Published: 2026-05-01 14:14 – Updated: 2026-05-01 14:14
VLAI?
Title
sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU
Summary
In the Linux kernel, the following vulnerability has been resolved: sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU Since commit 8e4f0b1ebcf2 ("bpf: use rcu_read_lock_dont_migrate() for trampoline.c"), the BPF prolog (__bpf_prog_enter) calls migrate_disable() only when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate(). Without CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled, so migration_disabled == 1 always means the task is truly migration-disabled regardless of whether it is the current task. The old unconditional p == current check was a false negative in this case, potentially allowing a migration-disabled task to be dispatched to a remote CPU and triggering scx_error in task_can_run_on_remote_rq(). Only apply the p == current disambiguation when CONFIG_PREEMPT_RCU is enabled, where the ambiguity with the BPF prolog still exists.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < 72c43eb2e334febe93018cfb68ae828f55c6e49e (git)
Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < b4992a9446bb9a639007bfd32bf5c5a7e30199e5 (git)
Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < 0c4a59df370bea245695c00aaae6ae75747139bd (git)
Create a notification for this product.
    Linux Linux Affected: 6.18
Unaffected: 0 , < 6.18 (semver)
Unaffected: 6.18.22 , ≤ 6.18.* (semver)
Unaffected: 6.19.12 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext_idle.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "72c43eb2e334febe93018cfb68ae828f55c6e49e",
              "status": "affected",
              "version": "8e4f0b1ebcf2180ab594f204f01279a666dadf3b",
              "versionType": "git"
            },
            {
              "lessThan": "b4992a9446bb9a639007bfd32bf5c5a7e30199e5",
              "status": "affected",
              "version": "8e4f0b1ebcf2180ab594f204f01279a666dadf3b",
              "versionType": "git"
            },
            {
              "lessThan": "0c4a59df370bea245695c00aaae6ae75747139bd",
              "status": "affected",
              "version": "8e4f0b1ebcf2180ab594f204f01279a666dadf3b",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/sched/ext_idle.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": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.22",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.12",
                  "versionStartIncluding": "6.18",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
                  "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: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU\n\nSince commit 8e4f0b1ebcf2 (\"bpf: use rcu_read_lock_dont_migrate() for\ntrampoline.c\"), the BPF prolog (__bpf_prog_enter) calls migrate_disable()\nonly when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate().\nWithout CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled,\nso migration_disabled == 1 always means the task is truly\nmigration-disabled regardless of whether it is the current task.\n\nThe old unconditional p == current check was a false negative in this\ncase, potentially allowing a migration-disabled task to be dispatched to\na remote CPU and triggering scx_error in task_can_run_on_remote_rq().\n\nOnly apply the p == current disambiguation when CONFIG_PREEMPT_RCU is\nenabled, where the ambiguity with the BPF prolog still exists."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-01T14:14:32.217Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/72c43eb2e334febe93018cfb68ae828f55c6e49e"
        },
        {
          "url": "https://git.kernel.org/stable/c/b4992a9446bb9a639007bfd32bf5c5a7e30199e5"
        },
        {
          "url": "https://git.kernel.org/stable/c/0c4a59df370bea245695c00aaae6ae75747139bd"
        }
      ],
      "title": "sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31734",
    "datePublished": "2026-05-01T14:14:32.217Z",
    "dateReserved": "2026-03-09T15:48:24.137Z",
    "dateUpdated": "2026-05-01T14:14:32.217Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-31734",
      "date": "2026-05-05",
      "epss": "0.00017",
      "percentile": "0.04061"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31734\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-05-01T15:16:36.030\",\"lastModified\":\"2026-05-01T15:24:14.893\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nsched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU\\n\\nSince commit 8e4f0b1ebcf2 (\\\"bpf: use rcu_read_lock_dont_migrate() for\\ntrampoline.c\\\"), the BPF prolog (__bpf_prog_enter) calls migrate_disable()\\nonly when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate().\\nWithout CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled,\\nso migration_disabled == 1 always means the task is truly\\nmigration-disabled regardless of whether it is the current task.\\n\\nThe old unconditional p == current check was a false negative in this\\ncase, potentially allowing a migration-disabled task to be dispatched to\\na remote CPU and triggering scx_error in task_can_run_on_remote_rq().\\n\\nOnly apply the p == current disambiguation when CONFIG_PREEMPT_RCU is\\nenabled, where the ambiguity with the BPF prolog still exists.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0c4a59df370bea245695c00aaae6ae75747139bd\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/72c43eb2e334febe93018cfb68ae828f55c6e49e\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/b4992a9446bb9a639007bfd32bf5c5a7e30199e5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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.



Detection rules are retrieved from Rulezet.