Vulnerability-Lookup

GHSA-VR6V-MM3H-F67M

Vulnerability from github – Published: 2026-05-01 15:30 – Updated: 2026-05-07 18:30

Details

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 ?

5.5 (Medium)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-31734"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-01T15:16:36Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-vr6v-mm3h-f67m",
  "modified": "2026-05-07T18:30:34Z",
  "published": "2026-05-01T15:30:34Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31734"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c4a59df370bea245695c00aaae6ae75747139bd"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72c43eb2e334febe93018cfb68ae828f55c6e49e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b4992a9446bb9a639007bfd32bf5c5a7e30199e5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

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

Vulnerability from cvelistv5 – Published: 2026-05-01 14:14 – Updated: 2026-05-11 22:14

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

Linux

References

3 references

URL	Tags
https://git.kernel.org/stable/c/72c43eb2e334febe9…
https://git.kernel.org/stable/c/b4992a9446bb9a639…
https://git.kernel.org/stable/c/0c4a59df370bea245…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < 72c43eb2e334febe93018cfb68ae828f55c6e49e (git) Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < b4992a9446bb9a639007bfd32bf5c5a7e30199e5 (git) Affected: 8e4f0b1ebcf2180ab594f204f01279a666dadf3b , < 0c4a59df370bea245695c00aaae6ae75747139bd (git)
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)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "72c43eb2e334febe93018cfb68ae828f55c6e49e",
              "status": "affected",
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              "versionType": "git"
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            {
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            },
            {
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            }
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          "versions": [
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              "version": "6.18"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
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              "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",
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          "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."
        }
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      "providerMetadata": {
        "dateUpdated": "2026-05-11T22:14:43.725Z",
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        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/0c4a59df370bea245695c00aaae6ae75747139bd"
        }
      ],
      "title": "sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU",
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    "cveId": "CVE-2026-31734",
    "datePublished": "2026-05-01T14:14:32.217Z",
    "dateReserved": "2026-03-09T15:48:24.137Z",
    "dateUpdated": "2026-05-11T22:14:43.725Z",
    "state": "PUBLISHED"
  },
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}

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.

Action not permitted

GHSA-VR6V-MM3H-F67M

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

Tags

Sightings

Nomenclature