Vulnerability-Lookup

GHSA-C3CW-2PJ9-44QJ

Vulnerability from github – Published: 2026-10-18 18:32 – Updated: 2026-10-18 18:32

Details

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()

bpf_mem_cache_free_rcu() uses this_cpu_ptr() which requires migration to be disabled. All callers of rhtab_delete_elem() disable migration except __rhtab_map_lookup_and_delete_batch(), which calls it under rcu_read_lock() only.

On CONFIG_PREEMPT_RCU, rcu_read_lock() does not disable preemption or migration, so the task can migrate between CPUs during the delete loop, causing this_cpu_ptr() to trigger:

BUG: using smp_processor_id() in preemptible [00000000] code

Fix by wrapping the delete loop in migrate_disable()/migrate_enable() in __rhtab_map_lookup_and_delete_batch(), matching the migration protection that the other callers already provide.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98787"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:32Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()\n\nbpf_mem_cache_free_rcu() uses this_cpu_ptr() which requires migration\nto be disabled. All callers of rhtab_delete_elem() disable migration\nexcept __rhtab_map_lookup_and_delete_batch(), which calls it under\nrcu_read_lock() only.\n\nOn CONFIG_PREEMPT_RCU, rcu_read_lock() does not disable preemption or\nmigration, so the task can migrate between CPUs during the delete loop,\ncausing this_cpu_ptr() to trigger:\n\n  BUG: using smp_processor_id() in preemptible [00000000] code\n\nFix by wrapping the delete loop in migrate_disable()/migrate_enable()\nin __rhtab_map_lookup_and_delete_batch(), matching the migration\nprotection that the other callers already provide.",
  "id": "GHSA-c3cw-2pj9-44qj",
  "modified": "2026-10-18T18:32:03Z",
  "published": "2026-10-18T18:32:03Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98787"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/94f41ec5fa578765b74ad5736c2f029e7aabc46d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/de020dc8049bfb2b22e3b6d99c031feb2e22d112"
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  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98787 (GCVE-0-2026-98787)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:48 – Updated: 2026-10-19 09:25

Title

bpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch() bpf_mem_cache_free_rcu() uses this_cpu_ptr() which requires migration to be disabled. All callers of rhtab_delete_elem() disable migration except __rhtab_map_lookup_and_delete_batch(), which calls it under rcu_read_lock() only. On CONFIG_PREEMPT_RCU, rcu_read_lock() does not disable preemption or migration, so the task can migrate between CPUs during the delete loop, causing this_cpu_ptr() to trigger: BUG: using smp_processor_id() in preemptible [00000000] code Fix by wrapping the delete loop in migrate_disable()/migrate_enable() in __rhtab_map_lookup_and_delete_batch(), matching the migration protection that the other callers already provide.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6820 records in the last 180 days details

References

2 references

URL	Tags
https://git.kernel.org/stable/c/94f41ec5fa578765b…
https://git.kernel.org/stable/c/de020dc8049bfb2b2…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 818e0084822742fc00eacbf5df3476a5e72c7d0e , < 94f41ec5fa578765b74ad5736c2f029e7aabc46d (git) Affected: 818e0084822742fc00eacbf5df3476a5e72c7d0e , < de020dc8049bfb2b22e3b6d99c031feb2e22d112 (git)
Linux	Linux	Affected: 7.2 Unaffected: 0 , < 7.2 (semver) Unaffected: 7.2.10 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix missing migration protection in __rhtab_map_lookup_and_delete_batch()\n\nbpf_mem_cache_free_rcu() uses this_cpu_ptr() which requires migration\nto be disabled. All callers of rhtab_delete_elem() disable migration\nexcept __rhtab_map_lookup_and_delete_batch(), which calls it under\nrcu_read_lock() only.\n\nOn CONFIG_PREEMPT_RCU, rcu_read_lock() does not disable preemption or\nmigration, so the task can migrate between CPUs during the delete loop,\ncausing this_cpu_ptr() to trigger:\n\n  BUG: using smp_processor_id() in preemptible [00000000] code\n\nFix by wrapping the delete loop in migrate_disable()/migrate_enable()\nin __rhtab_map_lookup_and_delete_batch(), matching the migration\nprotection that the other callers already provide."
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      "providerMetadata": {
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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.

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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.
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