Vulnerability-Lookup

GHSA-H63H-WCX8-JM4R

Vulnerability from github – Published: 2026-09-16 12:30 – Updated: 2026-09-16 15:31

Details

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

mm/page_alloc: don't spin_trylock() in NMI on UP

Patch series "mm/page_alloc: fixes for free_pages_nolock() on RT/UP".

Pre-existing bugs found by Sashiko during review of this other series: https://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/

I have not reproduced these bugs, and I suspect there is no real-world user that is affected by them.

This patch (of 2):

As noted in can_spin_trylock(), using this is unsafe in this context. commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side but missed the free side.

Impact: If BPF programs using these features in NMI (probably tracing) are present on non-SMP builds this might crash the kernel and is probably exploitable by local attackers for privilege escalation.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-90046"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-16T11:17:17Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: don\u0027t spin_trylock() in NMI on UP\n\nPatch series \"mm/page_alloc: fixes for free_pages_nolock() on RT/UP\".\n\nPre-existing bugs found by Sashiko during review of this other series:\nhttps://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/\n\nI have not reproduced these bugs, and I suspect there is no real-world\nuser that is affected by them.\n\n\nThis patch (of 2):\n\nAs noted in can_spin_trylock(), using this is unsafe in this context. \ncommit 620b46ed6ae17 (\"mm/page_alloc: return NULL early from\nalloc_frozen_pages_nolock() in NMI on UP\") fixed this on the alloc side\nbut missed the free side.\n\nImpact: If BPF programs using these features in NMI (probably tracing) are\npresent on non-SMP builds this might crash the kernel and is probably\nexploitable by local attackers for privilege escalation.",
  "id": "GHSA-h63h-wcx8-jm4r",
  "modified": "2026-09-16T15:31:08Z",
  "published": "2026-09-16T12:30:46Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90046"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/06c76d3c389ff504052f64b1acee44651bd847fa"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3105ae628fb785d48b49256468be4f21a7b3cfc0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/68a069b407303e71db371df85036101e8ff59280"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-90046 (GCVE-0-2026-90046)

Vulnerability from cvelistv5 – Published: 2026-09-16 10:33 – Updated: 2026-09-16 14:42

Title

mm/page_alloc: don't spin_trylock() in NMI on UP

Summary

In the Linux kernel, the following vulnerability has been resolved: mm/page_alloc: don't spin_trylock() in NMI on UP Patch series "mm/page_alloc: fixes for free_pages_nolock() on RT/UP". Pre-existing bugs found by Sashiko during review of this other series: https://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/ I have not reproduced these bugs, and I suspect there is no real-world user that is affected by them. This patch (of 2): As noted in can_spin_trylock(), using this is unsafe in this context. commit 620b46ed6ae17 ("mm/page_alloc: return NULL early from alloc_frozen_pages_nolock() in NMI on UP") fixed this on the alloc side but missed the free side. Impact: If BPF programs using these features in NMI (probably tracing) are present on non-SMP builds this might crash the kernel and is probably exploitable by local attackers for privilege escalation.

Severity

7.8 (High)


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

Assigner

Linux mitre root

References

3 references

URL	Tags
https://git.kernel.org/stable/c/06c76d3c389ff5040…
https://git.kernel.org/stable/c/68a069b407303e71d…
https://git.kernel.org/stable/c/3105ae628fb785d48…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 8c57b687e8331eb80e302a2c528b18b966a9ac7a , < 06c76d3c389ff504052f64b1acee44651bd847fa (git) Affected: 8c57b687e8331eb80e302a2c528b18b966a9ac7a , < 68a069b407303e71db371df85036101e8ff59280 (git) Affected: 8c57b687e8331eb80e302a2c528b18b966a9ac7a , < 3105ae628fb785d48b49256468be4f21a7b3cfc0 (git)
Linux	Linux	Affected: 6.15 Unaffected: 0 , < 6.15 (semver) Unaffected: 6.18.51 , ≤ 6.18.* (semver) Unaffected: 7.2.5 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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{
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          "defaultStatus": "unaffected",
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          "vendor": "Linux",
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              "status": "affected",
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            }
          ]
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          "versions": [
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              "version": "6.15"
            },
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              "lessThan": "6.15",
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              "version": "0",
              "versionType": "semver"
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            {
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              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
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          "nodes": [
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              "cpeMatch": [
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                }
              ],
              "negate": false,
              "operator": "OR"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm/page_alloc: don\u0027t spin_trylock() in NMI on UP\n\nPatch series \"mm/page_alloc: fixes for free_pages_nolock() on RT/UP\".\n\nPre-existing bugs found by Sashiko during review of this other series:\nhttps://lore.kernel.org/all/20260703-alloc-trylock-v5-0-c87b714e19d3@google.com/\n\nI have not reproduced these bugs, and I suspect there is no real-world\nuser that is affected by them.\n\n\nThis patch (of 2):\n\nAs noted in can_spin_trylock(), using this is unsafe in this context. \ncommit 620b46ed6ae17 (\"mm/page_alloc: return NULL early from\nalloc_frozen_pages_nolock() in NMI on UP\") fixed this on the alloc side\nbut missed the free side.\n\nImpact: If BPF programs using these features in NMI (probably tracing) are\npresent on non-SMP builds this might crash the kernel and is probably\nexploitable by local attackers for privilege escalation."
        }
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          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - free_pages_nolock is reached from local BPF programs (arena/bpf_map_alloc_pages and related nolock helpers) running in NMI, typically a BPF_PROG_TYPE_PERF_EVENT overflow handler installed via bpf()/perf_event_open. It is not reachable from unauthenticated network packets or in-kernel servers such as ksmbd/nfsd.\nAC:L - Scoring assumes a uniprocessor (!CONFIG_SMP) kernel, a reasonable embedded/IoT deployment. An attacker who can attach a BPF perf-event program controls the NMI that calls free_pages_nolock and can concurrently run page-allocator work so the NMI interrupts zone-\u003elock; the in-tree slub_kunit NMI overflow test shows this reentry is reliably triggerable.\nPR:L - Loading the NMI BPF program requires CAP_BPF and CAP_PERFMON, which are sub-root capabilities. BPF tokens can delegate those checks into a non-init user namespace in plausible container/tracing deployments, so this is treated as low privileges rather than init-namespace root.\nUI:N - The attacker loads the BPF program, programs the PMU, and drives local memory activity themselves. No separate victim action such as mounting a filesystem or opening a crafted file is required.\nS:U - Re-entrant buddy/zone-lock corruption stays inside the kernel\u0027s own security authority and yields local privilege escalation, not a VM, IOMMU, or other cross-boundary escape.\nC:H - Nested spin_trylock of zone-\u003elock on UP lets the NMI mutate buddy freelists while the interrupted context is mid-update, corrupting page-allocator metadata. That overlapping-page primitive can be leveraged for arbitrary kernel memory disclosure.\nI:H - The same freelist corruption is a well-known arbitrary-write and control-flow hijack primitive, and the fix commit states the bug is probably exploitable by local attackers for privilege escalation.\nA:H - Re-entrant zone-lock and buddy updates crash the kernel via oops, panic, or a DEBUG_SPINLOCK BUG on UP, which is a full availability loss."
            }
          ]
        }
      ],
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        "dateUpdated": "2026-09-16T14:42:01.386Z",
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          "url": "https://git.kernel.org/stable/c/68a069b407303e71db371df85036101e8ff59280"
        },
        {
          "url": "https://git.kernel.org/stable/c/3105ae628fb785d48b49256468be4f21a7b3cfc0"
        }
      ],
      "title": "mm/page_alloc: don\u0027t spin_trylock() in NMI on UP",
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    "cveId": "CVE-2026-90046",
    "datePublished": "2026-09-16T10:33:43.156Z",
    "dateReserved": "2026-09-11T19:38:34.783Z",
    "dateUpdated": "2026-09-16T14:42:01.386Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2"
}

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.

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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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